High Voltage 3 Watt Audio Power Amplifier

The LM4954 is an audio power amplifier primarily designed for demanding applications in mobile phones and other portable communication device applications. It is capable of delivering 2.4 Watts of continuous average power to an 8 BTL load with less than 1% THD+N from a 7V_DC power supply. Boomer audio power amplifiers are designed specifically to provide high quality output power with a minimal number of external components. The LM4954 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for lower-power portable applications where minimal space and power consumption are primary requirements.

High Voltage 3 Watt Audio Power Amplifier Circuit Diagram

The LM4954 features a low-power consumption global shutdown mode which is achieved by driving the shutdown pin with logic low. Additionally, the LM4954 features an internal thermal shutdown protection mechanism.

The LM4954 contains advanced pop & click circuitry which eliminates noises that would otherwise occur during turn-on and turn-off transitions.

The LM4954 is unity-gain stable and can be configured by external gain-setting resistors.

Key Specification:

Wide Power Supply Voltage Range	2.7 <= VDD <= 9V
Output Power: VDD = 7V, 1% THD+N	2.4W (typ)
Quiescent power supply current	3mA (typ)
PSRR: VDD = 5V and 3V at 217Hz	80dB (typ)
Shutdown power supply current	0.01µA (typ)

Features:

No output coupling capacitors, snubber networks or bootstrap capacitors required

Unity gain stable

Externally configurable gain

Ultra low current active low shutdown mode

BTL output can drive capacitive loads up to 100pF

"Click and pop" suppression circuitry

2.7V - 9.0V operation

Available in space-saving microSMD package

Applications

Mobile Phones

PDAs

Source: http://www.ecircuitslab.com/2011/06/high-voltage-3-watt-audio-power.html

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Automatic Room Power Control

          An ordinary automatic room power control circuit has only one light sensor. So when a person enters the room it gets one pulse and the lights come ‘on.’ When the person goes out it gets another pulse and the lights go ‘off.’ But what happens when two persons enter the room, one after the other? It gets two pulses and the lights remain in ‘off’ state. The circuit described here overcomes the above-mentioned problem. It has a small memory which enables it to automatically switch ‘on’ and switch ‘off’ the lights in a desired fashion.

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   The circuit uses two LDRs which are placed one after another (separated by a distance of say half a metre) so that they may separately sense a person going into the room or coming out of the room. Outputs of the two LDR sensors, after processing, are used in conjunction with a bicolour LED in such a fashion that when a person gets into the room it emits green light and when a person goes out of the room it emits red light, and vice versa. These outputs are simultaneously applied to two counters.

   One of the counters will count as +1, +2, +3 etc when persons are coming into the room and the other will count as -1, -2, -3 etc when persons are going out of the room. These counters make use of Johnson decade counter CD4017 ICs. The next stage comprises two logic ICs which can combine the outputs of the two counters and determine if there is any person still left in the room or not.

   Since in the circuit LDRs have been used, care should be taken to protect them from ambient light. If desired, one may use readily available IR sensor modules to replace the LDRs. The sensors are installed in such a way that when a person enters or leaves the room, he intercepts the light falling on them sequentially—one after the other.

   When a person enters the room, first he would obstruct the light falling on LDR1, followed by that falling on LDR2. When a person leaves the room it will be the other way round. In the normal case light keeps falling on both the LDRs, and as such their resistance is low (about 5 kilo-ohms). As aresult, pin 2 of both timers (IC1 and IC2), which have been configured as monostable flip-flops, are held near the supply voltage (+9V).

   When the light falling on the LDRs is obstructed, their resistance becomes very high and pin 2 voltages drop to near ground potential, thereby triggering the flip-flops. Capacitors across pin 2 and ground have been added to avoid false triggering due to electrical noise.

   When a person enters the room, LDR1 is triggered first and it results in triggering of monostable IC1. The short output pulse immediately charges up capacitor C5, forward biasing transistor pair T1-T2. But at this instant the collectors of transistors T1 and T2 are in high impedance state as IC2 pin 3 is at low potential and diode D4 is not conducting.

   But when the same person passes LDR2, IC2 monostable flip-flop is triggered. Its pin 3 goes high and this potential is coupled to transistor pair T1-T2 via diode D4. As a result transistor pair T1-T2 conducts because capacitor C5 retains the charge for some time as its discharge time is controlled by resistor R5 (and R7 to an extent). Thus green LED portion of bi-colour LED is lit momentarily.

   The same output is also coupled to IC3 for which it acts as a clock. With entry of each person IC3 output (high state) keeps advancing. At this stage transistor pair T3-T4 cannot conduct because output pin 3 of IC1 is no longer positive as its output pulse duration is quite short and hence transistor collectors are in high impedance state.

   When persons leave the room, LDR2 is triggered first, followed by LDR1. Since the bottom half portion of circuit is identical to top half, this time, with the departure of each person, red portion of bicolour LED is lit momentarily and output of IC4 advances in the same fashion as in case of IC3.

   The outputs of IC3 and those of IC4 (after inversion by inverter gates N1 through N4) are ANDed by AND gates (A1 through A4) and then wire ORed (using diodes D5 through D8). The net effect is that when persons are entering, the output of at least one of the AND gates is high, causing transistor T5 to conduct and energise relay RL1. The bulb connected to the supply via N/O contact of relay RL1 also lights up.

   When persons are leaving the room, and till all the persons who entered the room have left, the wired OR output continues to remain high, i.e. the bulb continues to remains ‘on,’ until all persons who entered the room have left.

   The maximum number of persons that this circuit can handle is limited to four since on receipt of fifth clock pulse the counters are reset. The capacity of the circuit can be easily extended to handle up to nine persons by removing the connection of pin 1 from reset pin (15) and utilising Q1 to Q9 outputs of CD4017 counters. Additional inverters, AND gates and diodes will, however, be required.

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Usb Power Socket Circuit Diagram

Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100 mA of continuous current at 5V to the peripherals that are connected to the bus. So a USB port can be used, without any trouble, for powering 5V DC operated tiny electronic gadgets. Nowadays, many handheld devices (for instance, portable reading lamps) utilise this facility of the USB port to recharge their built-in battery pack with the help of an internal circuitry.Usually 5V DC, 100mA current is required to satisfy the input power demand. Fig. 1 shows the circuit of a versatile USB power socket that safely converts the 12V battery voltage into stable 5V.

Circuit diagram:

Fig. 1: Circuit of USB power socket

This circuit makes it possible to power/recharge any USB power-operated device, using in-dash board cigar lighter socket of your car. The DC supply available from the cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1). Capacitor C1 buffers any disorder in the input supply.Resistors R1 and R2 regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket.

Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage. Assemble the circuit on a general-purpose PCB and enclose in a slim plastic cabinet along with the indicator and USB socket. While wiring the USB outlet, ensure correct polarity of the supply. For interconnection between the cigar plug pin and the device, use a long coil cord as shown in Fig. 2. Pin configuration of LM317L is shown in Fig. 3.

Author : T.K. Hareendran - Source : EFY Mag

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High Power Car Battary Eliminator

To operate car audio (or video) system from household 230V AC mains supply, you need a DC adaptor. DC adaptors available in the market are generally costly and supply an unregulated DC. To overcome these problems, an economical and reliable circuit of a high-power, regulated DC adaptor using reasonably low number of components is presented here.  Transformer X1 steps down 230V AC mains supply to around 30V AC, which is then rectified by a bridge rectifier comprising 5406 rectifier diodes D1 through D4. The rectified pulsating DC is smoothed by two 4700μF filter capacitors C1 and C2. The next part of the circuit is a seriestransistor regulator circuit realised using high-power transistor 2N3773 (T1). 

 

Fixed-base reference for the transistor is taken from the output pin of 3-pin regulator IC1 (LM 7806). The normal output of IC1 is raised to about 13.8 volts by suitably biasing its common terminal by components ZD1 and LED1. This simple arrangement provides good, stable voltcuit age reference at a low cost. LED1 also works as an output indicator.Finally, a crowbar-type protection circuit is added. If the output voltage exceeds 15V due to some reason such as component failure, the SCR fires because of the breakdown of zener ZD2. Once SCR fires, it presents a short-circuit across the unregulated DC supply, resulting in the blowing of fuse F1 instantly. This offers guaranteed protection to the equipment connected and to the circuit itself.

 

This circuit can be assembled using a small general-purpose PCB. A goodquality heat-sink is required for transistor T1. Enclose the complete circuit in a readymade big adaptor cabinet as shown in the figure.

Streampowers

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All Constructing Various DC Power Supplies Projects

One of the basic building blocks of electronics project is building your own DC power supplies from an AC source of 110 V.A.C or 220 V.A.C.The common DC voltages that are necessary to power up the devices are usually in the range of three V DC to 30 V DC. Usually the fixed types of DC voltages are 5V, 9V, 12V, 15V & 18V DC. With the advancement of know-how, lots of devices are using one.8 V DC these days. S M P S is becoming common these days as the demand for miniaturization due to space constraints increases.

Take note that for linear power supply projects, you need to make use of a step down power transformer to step down the AC voltage from the line voltage of 110 V.A.C or 220 V.A.C before using it to supply to the diode bridge.

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Switching Power Supply Using the LMZ14202H

Using the LMZ14202H power switching controller, can be designed a very simple switching power supply circuit that can provide a fixed output voltage covering a wide range of voltages .

Switching Power Supply Circuit diagram

This power switching power supply electronic project will provide a fixed output voltage between 5 and 30 volt from an input voltage between 8 and 42 volt at a maximum output current of 2 ampere . This circuit project power supply require few external electronic parts and can be configured very easy . In the table bellow you can see components value that are required for different output voltage

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Ultra Low Power LCD Indicator

This circuit serves as an ultra-low power replacement for multiple LED on-off indicators. It also has the advantage of being easy to read in full daylight. With the parts shown, it is possible to display four bits of information.

The display that I used has three digits and 2 decimal points for a total of 23 segments. Different groupings of segments can be used for the four indicators. I chose to use three squares (shown) and the three lower segments together (not shown) for the four indicators. Many other combinations could be used, one possibility would be to hard-wire numbers or letters out of each of the digits. Other LCD displays could also be used for different effects.

Circuit Diagram

A part that doesnt exist as far as I know, but should, is a single pixel LCD indicator (2 wire). An LCD manufacturer could probably make a lot of money with such a part. If such a thing exists, Id love to hear about it.

Specifications:
Operating Voltage: 3-15V (5V Nominal) DC
Operating Current: 250 microamps to 1 milliamp (400 microamps at 5V)
Operating Frequency: approximately 60 Hz

Theory:
The 7555 IC (CMOS 555 timer) generates a square wave clock signal at approximately 60 hz. This signal is sent to the LCD backplane and the inputs of the four CMOS 4070 XOR gates. If the other input (ind*) of an XOR gate is low, the gates output is a square wave that is in phase with the clock signal. If the ind* input is high, the gates output is out of phase with the clock.

Sending a signal to an LCD segment that is in phase with the backplane signal causes the display to stay blank. Sending an out of phase signal to the LCD segment causes an AC waveform to be applied to the segment which turns it black. Multiple segments are wired in parallel to generate the desired display patterns. The LCD segments require a tiny amount of current to operate, the CMOS gates also take very little power, hence the efficient nature of the circuit. It is necessary to tie the unused segments to the LCD backplane, otherwise they may partially turn on.

If more dislay bits are needed, additional XOR gates can be connected in the same manner. Up to 23 XOR gates could be used to drive the entire display, but a microprocessor and driver software would probably be easier to put together. By generating all of the signals with a microprocessor, all of the driving circuitry can be eliminated.

Other logic families could be used to make this circuit, it should work with a standard 555 timer chip and a 74LS86 XOR gate (different pinout), for example.

Some LCDs may not operate at very cold temperatures, an engineer at Lumex said that their components will work from -30C to +75C.

Construction:
The circuit was built on a standard prototyping plug board. All of the parts can be purchased for under ten dollars.

Use:
The four inputs of the CMOS 4070 IC can connect to outputs on a microprocessor, or any other logic output that needs monitoring. The supply voltage of this circuit should be the same as the driving logics supply voltage.

Parts:
1X Lumex LCD-S301C31TR 3 digit LCD display (from Digi-Key), or equivalent
1X CMOS 4070 quad XOR Gate, a CMOS 4030 should also work.
1X 7555 CMOS 555 timer chip
2X 100nF capacitor
1X 100uF 25V electrolytic capacitor
1X 10K 1/4W resistor
1X 100K 1/4W resistor

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230 V AC To 400 V DC Power Supply Circuit Diagram

Description

               A lot of students are who dont know how to convert 230 volt AC to 400 DC. So today I am published   230 V AC to 400 V DC circuit diagram on my blog. Working principle of this circuit diagram is very simple. You already knew the working principle of a bridge rectifier. This circuit is same as bridge rectifier and the working principle is also same. The fuse is used to protect the circuit, if the current is greater than 1 A.


Parts List

Component No:	Value
F1	1 A
B1	IN4007
C1	470MF/450V
V1	230 V AC

Source by : link

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Simple Audio Power Meter Circuit

This simple circuit indicates the amount of power that goes to a loudspeaker. The dual-color LED shows green at an applied power level of about 1 watt. At 1.5 watts it glows orange and above 3 watts it is bright red. The circuit is connected in parallel with the loudspeaker connections and is powered from the audio signal. The additional load that this represents is 470 Ohm (R1//R3) will not be a problem for any amplifier. During the positive half cycle of the output signal the green LED in the dual-color LED will be turned on, provided the voltage is sufficiently high.

At higher output voltages, T1 (depending on the voltage divider R2/R1) will begin to conduct and the green LED will go out. During the negative half cycle the red LED is driven via R3 and will turn on when the voltage is high enough. In the transition region (where T1 conducts more and more and ‘throttles’ the green LED as a result) the combination of red/green gives the orange colour of the dual-LED. By choosing appropriate values for the resistors the power levels can be adjusted to suit.

 

Circuit diagram:

Audio Power Meter Circuit Diagram

 

The values selected here are for typical living room use. You will be surprised at how loud you have to turn your amplifier up before you get the LEDs to go! The resistors can be 0.25 W types, provided the amplifier does not deliver more than 40 W continuously. Above this power the transistor will not be that happy either, so watch out for that too. Because T1 is used in saturation, the gain (Hfe) is not at all important and any similar type can be used. The power levels mentioned are valid for 4-Ohm speakers. For 8-Ohm speakers all the resistor values have to be divided by two.

 

 

 

http://streampowers.blogspot.com/2012/06/simple-audio-power-meter-circuit.html 

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Dark Sensitive Power Switch Circuit Diagram Using LDR

Description

Circuit showing a Dark Sensitive Power Switch .Here we have used a ldr and a ordinary transistor for making this circuit
.Connect any 230 volt equipment at the load .You need a 9 volt power supply
Components Required

         Resistor

                     10 k , 680 R

          Transistor

                        BC 548

          Diode

                   IN 4007

         Relay

         LDR

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Hilux Pickup Power Window Control System Connectors Wiring Diagram

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About Honda Cb400 And Cb450 Wiring Diagram And Schematics Here.



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Of This Bosch Alternator S Internal Circuits Is Given Below.



Electrical Wiring Diagram 1992 Here 40 Pages Of Pdf File Docs.



Voltage Specs Wiring For The Alternator Regulator Justanswer.



Fig 01 Basic Alternator Schematic Diagram.



Wiring Diagram And Body Electrical Parts Schematic This Covers.

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Steady State Reactive Power Capability

A typical alternator curve of reactive power (kVAR)capability. A reasonable guideline is that a generator set can carry up to 10 percent of its rated kVAR capability in leading power factor loads without being damaged or losing control of output voltage. The most common sources of leading power factor are lightly loaded UPS systems with input filters and power factor correction devices for motors. Loading the generator set with lagging power factor loads prior to the leading power factor loads can improve stability.

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GPS Synchronization for Power System

Generic GPS synchronization architecture for power system

Precision timing is required for monitoring and control of electrical power networks where power system reliability is important.  Circuit breaker control schemes require precise timing to ensure proper operation, and Sequence of Events Recording systems report events with one-millisecond precision to aid diagnostics and troubleshooting.  Typical “critical power” applications include electric utility networks, data centres, hospitals, water treatment plants, refineries, and other process industries.

Global Positioning Systems can be used to provide a precise time reference for power system devices in an electrical network, ensuring time synchronization even across great distances.  A generic GPS system architecture is shown below:

A GPS antenna receives a time signal from the system of satellites orbiting the Earth.  A GPS receiver accepts raw time data from the antenna and converts it to one or more time protocols.
Each power system device accepts a sync pulse, usually via a dedicated, high-speed digital input.  The device then sets its internal clock by decoding the supported time protocol.  Several time protocols are available, each with its advantages:

• IRIG-B — time codes originally developed by the US military and widely used by electric utilities and others, especially in the United States. IRIG-B is typically distributed as a DC level shift (unmodulated IRIG-B) with 100 pulses per second.  Examples of devices which implement IRIG-B include PowerLogic ION-8600 meters from Schneider Electric and SER-3200 event recorders from Cyber Sciences.

• DCF77 — standard time protocol well-suited to power applications because it requires less processor overhead than IRIG-B, yet offers equivalent accuracy. The 24Vdc pulse provides a complete date/time string once every minute.  The DCF77 signal is broadcast from Germany and can be accessed from most of Europe via a dedicated DCF77 receiver.  Alternatively, a GPS receiver can be used to accept a GPS signal, convert this to DCF77, and distribute the signal to multiple devices.  Examples of devices which support DCF77 include PowerLogic series CM3000 and CM4000 meters, PM870 meters, and Quantum PLCs using an ERT module, by Schneider Electric.  (More on DCF77)

• 1per10 — time synchronization protocol used by Sepam relays by Schneider Electric. One pulse every 10 seconds provides a precise time reference enabling Sepam relay clocks to maintain accurate time and date.  In fact, an approximate date and time is provided to Sepam by some other means (e.g., supervisory software), and the GPS time-sync pulse is used to achieve higher accuracy.  (More on 1per10)

Network Time Protocol is a web protocol used to provide a time reference over an Ethernet network or even the Internet.  However, the accuracy that can be achieved with this approach is normally on the order of one second – not sufficient for the one-millisecond precision required in most critical power applications.

A relatively new standard for precision time synchronization is defined by the IEEE in standard IEEE-1588 (also known as “Precision Time Protocol” or PTP).  Using the IEEE-1588 protocol, devices can achieve sub-millisecond accuracy over an Ethernet network.  However, special Ethernet hardware is required, and the protocol is not yet widely available in electrical power devices.  In the future, it is likely to be implemented widely in power system, in conjunction with GPS technology.

GPS time synchronization is especially useful when power system devices are located in different physical locations, such as several buildings in a campus arrangement or multiple substations separated by great distances.

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1 25V to 25V To DC power supply

This is a DC power supply circuit.This circuit is based on LM317 Variable Regulator.This Regulator needs at least 28v(DC).Then it will out put 1.25v to 25v DC.So I suppose this would be an important circuit for you all.# 5K ohm Change If you want to change the out put voltage
# This circuit supplies 1.3A.

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PC Power Saver

This circuit is designed to help minimise the  quiescent power consumption of PCs and  notebooks, the usage of simply our previous buddy the 555  timer and a relay as the major parts. The  circuit itself dissipates round zero.5 W in operation (that is, when the linked PC is on);  when switched off (with the relay not energised) the entire power draw is precisely zero. A prerequisite for the circuit is a PC or note e-book with a USB or PS/2 keyboard socket that  is energyed best when the PC is on. The power saver can be used to change PCs  and even whole multi-way extension leads. The unit can additionally be constructed  into  an  ordinary  mains  adaptor (which will must have an earth  pin!) because the photograph of the  creator‘s prototype shows. The  PC is plugged in to the socket  at the output of the ability saver  unit, and an extra connection  is made to the keep watch over enter of  the unit from a PS/2 (keyboard or mouse) socket or USB port. Only  the 5 V provide line of the interface is used.

 

  

PC Power Saver Image

When button S1 on the facility saver  is pressed the unit turns on, and the  monostable shaped by using the 555 timer is  brought about by means of the network composed with the aid of  R4 and C7. This drives relay RE1, whose contacts close. The connected PC isn't anyw tentatively powered up by means of the relay for a length  determined  by  P1  (approximately in the vary from 5 s to 10 s). If, all through this interval, the PC fails to indicate  that it is alive through supplying 5 V from its USB or  PS/2 connector (that is, if you don't change  it on), the monostable duration will expire, the  relay will drop out and any related device  will be energyed down. No further current will  be drawn from the provision, and, after all, it  might not be that that you may imagine to turn the PC on. When-ever you want to have to show the PC on, you must  always press the button on the ability saver  quickly earlier thanhand. 

If, however, 5 V is delivered through the PC to the  input of optocoupler IC2 earlier than the monostable occasions out (which will be the case if the  PC is changeed on all over that length), the  transistor within the optocoupler will conduct  and discharge capacitor C6. The monostable  will now stay prompted and the relay will  stay energised except the PC is changeed off  and power disappears from its USB or PS/2  interface. Then, after the monostable time  duration expires, the relay will drop out and the  power saver will disconnect itself from the primarys. There isn't any want to switch anything  else off: just shut down the gadget and the  power saver will deal with the stayder.

 

Circuit diagram :

PC Power Saver Circuit Diagram

 

It is additionally  imaginable to leave the computing device as it replaces its  tool, and the ability saver will do its job  quickly after the laptop shuts down. Power for the unit itself is obtained using a  simple provide circuit based around a miniature transformer. Alternatively, a 12 V mains  adaptor can be utilized, so lengthy as a relay with a  12 V coil voltage is used for RE1. In hellos proto-type the author used a relay with a 24 V coil  connected as proven immediately to the positive  facet of reservoir capacitor C2, the 555 being  energyed from 12 V regulated from that sup-ply using R1 and D1. A fixed resistor can of  path be used instead of P1 if desired. If the  adjustment vary of P1 isn't adequate (for  example if the PC energys up very slowly) the  monostable period may additionally be elevated via the usage of  a larger capacitor at C6.  The relay must have at the least two normally-open (or changeover) contacts rated at at  least eight A. The contact in parallel with S1 is used to provide energy to the device  itself, and the opposite contact carries  all of the current for the linked  PC  or  for  the  ex tension  lead  to  which  the  PC  and  peripherals  are  related. 

Pushbutton S1 must be rated for 230 VAC  (US: one hundred twenty VAC) operation: this is no place to  make economies. The coil current for the relay  floats thru LED D5, which must therefore  be a 20 mA sort. If a low-current LED is used,  a one hundred twenty Ω resistor may additionally be connected in parallel with it to carry the staying current.  The Fujitsu FTR-F1CL024R relay used in the  creator’s prototype has a rated coil present of  16.7 mA. Optocoupler IC2 offers isolation between  the circuit and the PC, and that is protected from  reverse polarity connection with the support of diode D4. The power saver must be constructed into an insulated enclosure and great care should be  taken to be certain that there is right kind isolation  between parts and wires carrying the  majors voltage and the other phases of the circuit. In phaseicular, the connection to the PC  and related elements (R6, C5, D4 and  IC2) must be in moderation arranged with as a minimum  a 6 mm hole between them and any section of  the circuit at majors potential.

 

Author : Wolfgang Gscheidle (Germany) - Copyright : Elektor

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Power up down Sequencer

Whether you’re speaking about a residence cinema  or a computer system, it’s very frequently the case  that the more than a few elements of the machine have  to be fliped on or off in a relatively explicit order,  or at least, routinely. Constructing this  sort of automation system is neatly inside the  functionality of any electronics enthusiast invaluable of the identify, however on this ‘all-digital’ age,  many of the circuits of this kind to be found  in newbie electronics magazines or web-sites use a microcontroller. Even although that  is indeed a logical solution (in  extra meanss than one!), and you  would probably even say the easiest one, it  does pose issues for all those  people who don’t (yet) have the  amenities for programming these  kinds  of  IC.  So  we  decided  to  offer you now an method that’s  very different, because it only makes use of a  simple, low cost, commonly-avail-able analogue integrated circuit,  which in fact doesn’t have to  be programmed. Our project in  reality makes use of as it’s ‘brain’ an LM3914,  a familiar IC from National Semiconductors,  usually  used  for  using  LED  VU  (volume  unit)  meters. 

Circuit diagram :

Power-up/down Sequencer Circuit Diagram

Before taking a look on the circuit  for  our  mission,  let ’s  just  remind ourselves that the IC has  one analogue enter and ten out-puts supposed for riding LEDs.  It can function in ‘point’ mode,  where the LEDs light up in flip,  from first to last, depending on  the enter voltage, but just one LED is lit at  any supplyn time. Alternatively  it will most probably function  in ‘bar’ mode (this is the mode usually used  for VU meters), and on this case, the LEDs light  up one after the other, in any such means as to create a strip of light (bar) that is longer or  shorter according to the enter voltage. This is  the mode selected for the LM3914 in the circuit described in some detail under. 

So as in an effort to control the AC energyed equipment  our  sequencer  is  meant  to manage, we're using solid-state relays — four, in our example, although which you can reduce or elevate this number, as so much as a most of ten. Since the enter instruments in solid-state relays are LEDs, they can be driven right away with the help of the LM3914 outputs, for the reason that that’s precisely what they’re designed for. As best 4 relays  are on hand, these are unfold across out-puts L2, L4, L6, and L8, however you can choose  any arrangement you prefer to go nicely with the quantity  of relays you want to have to make use of. 

Resistor R7 connected to pin 7 of the LM3914  units the current fed to the LEDs by means of the LM3914  outputs. Here, it’s been set to 20 mA, due to the fact  that's the price anticipated by the solid-state  relays chosen. The input voltage utilized to  pin 5 of the LM3914 is none instead of the  voltage present throughout capacitor C1 — and  that is the place the circuit is ingenious. When  the change is set to ‘on’, C1 charges slowly  thru R5, and the LEDs of the solid-state  relays on the outputs gentle one after another  as this voltage raises; in this approach, the gadgets  being keep watch overled are energyed up within the order you’ve chosen. To energy-down, all you have  to do is flip the change so that C1 discharges  through  R5,  and  the  LEDs  go  out  in  the  reverse order to that wherein they had been lit,  in turn energying down the devices connected to the solid-state relays. Easy, isn’t it? If you’re not pleased with the sequence velocity,  all you need do is increase or reduce the  value of R5 to be in a place to alter the pace one  manner or the different.

The circuit needs to be energyed from a volt-age of around 9 to 12 V, which doesn’t even  wish to be stabilized. A easy ‘plug-top’,  ‘wall wart’ or ‘battery eliminator’ unit will be  good, just so long as it is able to supply-ing enough current to power all the LEDs. As  the LED present is set by R7 to 20 mA per LED,  it’ll be simple for you to work out the current  required, according to the collection of solid-state relays you’re the use of. 

In our prototype the kind S216S02 relays  from Sharp have been used, primarily as a consequence of they  proved comfortably on hand via mail order. They even have the good thing about being compact,  and their switching capacity of sixteen A means  which you can dispense with a heatsink if you’re  the use of them for a computer or residence cinema  system, the place the present drawn via the vari-ous gadgets will more than likely be expected to stay under  1 A. These solid-state relays should be safe by a fuse, the score of which wants to  be chosen according to the current drawn  through the tools being powered. 

Also no longere the presence across the relay time periodinals of a VDR, sometimes called a GeMOV or  SiOV, intended to protect them from any spurious voltage spikes. You can use any sort  that ’s intended for operation on 250 VAC  with none problem. The prices of fuses F1  to F4 are after all going to rely upon the  load being secure. 

Construction of the circuit shouldn’t present any particular problem, however as the solid-state relays are connected right away to AC  power, it's very important to install it in a fully-insulated case; the case can additionally be used to  mount the energy outlet sockets keep watch overled  with the aid of the circuit. Note that sockets are female  elements.

Let’s simply finish this description with the sole  restrict imposed with the help of our circuit — but it’s  very simple to agree to, providen the intended  use. In order to remain brought about, the solid-state relays must elevate a minimal holding  present, which is 50 mA within the case of the  instruments we’ve selected. In sensible terms,  this just means that each and every of the devices powered by means of our sequencer should draw as a minimal  50 mA, or in different phrases roughly 12 VA at  230 VAC, or 25 VA at a hundred and twenty VAC.

Author :Christian Tavernier

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Simple Mini Power Inverter

Even robot systems occasionally need a negative supply voltage for some purpose or other, and in this kind of application in particular there is a need for an effective circuit that does  not  make  greater demands  then  necessary in terms of current or space. If a low current 5 V supply is needed and only +5 V is available, a natural manufacturer to turn  to  is  Maxim,  and indeed in this case they do not let us down.The best known integrated  circuit made by this company is the MAX232, a level shifter for serial ports with an integrated charge pump that does not need an external inductor.

Simple Mini Power Inverter   image:

Along the same lines, although with a more stable output voltage and higher efficiency, is the MAX660. The device can ‘mirror’ any input voltage between 1.5 V and 5.5 V. With a 5 V input the output is typically –4.7 V with a load of 100 mA. Efficiency at 10 mA is around 96 % and at 100 mA is around 88 %. With an open-circuit output the IC draws a quiescent current of just 120 μA.There is little to say about the circuit itself.

Simple Mini Power Inverter Circuit diagram:

The 0 Ω resistor on pin 1 selects the operating frequency. With R1 fitted, the circuit operates at 80 kHz; without it, at 10 kHz. The combination of L1 and C5 slightly reduces ripple on the output voltage; the choice of inductor is not as critical as it would be if it formed part of the switching circuit.Gerber files for the printed circuit board (which uses some SMD components) are available for download from the Elektor website, ref. 070279-11.zip. R1, C1 and C4 are 0603 SMDs and C3 is an SMD tantalum electrolytic capacitor. Either the MAX-660CSA or the MAX660M can be used; both come in SO8 packages. L1 is a 10 μH SMD inductor rated at 300 mA.

Source: http://www.ecircuitslab.com/2011/11/even-robot-systems-occasionally-need.html 

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UPS Power Supply

This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.
 

Notes:
This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit.
TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery. The circuit below simulates a working circuit with mains power applied: 

Between terminals VP1 and VP3 the nominal unregulated supply is available and a 5 Volt regulated supply between VP1 and VP2. Resistor R1 and D1 are the charging path for battery B1. D1 and D3 prevent LED1 being illuminated under power fail conditions. The battery is designed to be trickle charged, charging current defined as :-
 

(VP5 - 0.6 ) / R1
where VP5 is the unregulated DC power supply voltage.

D2 must be included in the circuit, without D2 the battery would charge from the full supply voltage without current limit, which would cause damage and overheating of some rechargeable batteries. An electrical power outage is simulated below:
 

 

Note that in all cases the 5 Volt regulated supply is maintained constantly, whilst the unregulated supply will vary a few volts.

Standby Capacity
The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere hour capacity of the battery. If you were using a 7A/h 12 Volt battery and load from the 5 Volt regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batteries would provide a longer standby time, and vice versa.

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11 W Stereo or 22 W Mono Power Amp

Integrated AF power amps have seen great improvements in recent years offering improved power and easier use. The TDA1519C from Philips contains two power amplifiers providing 11 W per channel stereo or 22 W mono when the two channels are connected in a bridge configuration. The special in-line SIL9P package outline allows the chip to be conveniently bolted to a suitable heatsink. The TDA1519CSP is the SMD version, in this case the heat sink is mounted over, and in contact with, the top surface of the chip.

11W Stereo Amplifier Circuit Diagram

The operating voltage of this device is from +6V to +17.5V. The two channels of the amplifier are different in that one channel, between pins 1 and 4, is a non-inverting amplifier, while the other between pins 9 and 6 is an inverting amplifier. It is therefore necessary in stereo operation, to wire the speakers so that one of them has its polarity reversed. Each amplifier has an input impedance of 60kΩ and a voltage gain of 40dB, i.e. 100 times. When both amplifier are used in a bridge configuration, the inputs are in parallel so that the input impedance will be 30kΩ.

22W Stereo Amplifier Circuit Diagram

A combined mute/standby function is provided on pin 8. In its simplest form this can be connected to the positive rail via a switch. When the switch is open the amplifier will be in standby mode and current consumption is less than 100µA. When the switch is closed, the amplifier will be operational. A circuit is also shown that uses the mute input to prevent the annoying switch-on plop heard when power amps are first switched on This is caused by the rush of current to charge capacitors C1 and C2.

Mute/Standby Switch Circuit Diagram

The circuit shown generates a ramp voltage, which is applied to pin 8. At switch on, as the voltage rises from 3.3 V to 6.4 V, the amplifier will switch out of standby mode and into mute mode allowing C1 and C2 to charge. Only when the ramp voltage on pin 8 reaches 8.5V will the amplifier switch into active mode. Protection built into the TDA1519C would seem to make it almost foolproof. The two outputs can be shorted to either of the supply rails and to each other. A thermal shutdown will prevent overloading and the power supply input is protected against accidental reversal of the supply leads up to 6V.

Source: http://www.ecircuitslab.com/2011/07/11-w-stereo-or-22-w-mono-power-amp.html

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