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Showing posts with label circuit. Show all posts

Showing posts with label circuit. Show all posts

Tuesday, December 24, 2013

Super Universal Battery Charger Circuit Diagram

The Super Universal Battery Charger Circuit Diagram output voltage is adjustable and regulated, and has an adjustable constant-current charging circuit that makes it easy to use with most NiCad batteries. The charger can charge a single cell or a number of series-conoected cells up to a maximum of 18 V.

Power transistors Ql and Q2 are conoected as series regulators to control the battery charger`s output voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistors Ql and Q2. Potentiometer R9 sets the output-voltage level. A current-sampling resistor, R8 (a 0.1-!J, 5-W unit), is conoected between the negative output lead and circuit ground. For each amp of charging that flows through R8, a 100 mV output is developed across it.

The voltage developed across RS is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor RIO. As the charging voltage across the battery begins to drop, the current through RS decreases. Then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signal`s circular path to regulate the battery`s charging current. The charging current can be set by adjusting RlO for the desired current. The circuit`s output voltage is set by R9.

Super Universal Battery Charger Circuit Diagram

Super Universal Battery Charger Circuit Diagram

Saturday, December 21, 2013

Build a Inexpensive Isolation Transformer Circuit Diagram

Build a Inexpensive Isolation Transformer Impromptus Setup Circuit Diagram. Using two 12-V filament or power transformers, an impromptu isolation transformer can be made for low-power (under 50 W) use in testing or servicing. SOI is an ordinary, duplex ac recept-able. Use heavy-wire connections between the 12-V windings because several amperes can flow.

Inexpensive Isolation Transformer Circuit Diagram

Inexpensive Isolation Transformer Circuit Diagram

Thursday, October 10, 2013

Short Circuit Protection With A MOSFET

If you have an application in which a MOSFET is already used to switch a load, it is relatively easy to add short-circuit or overload protection. Here we make use of the internal resistance RDS(ON), which produces a voltage drop that depends on the amount of current flowing through the MOSFET. The voltage across the internal resistance can be sensed using simple comparator or even a transistor, which switches on at a voltage of around 0.5V. You can thus avoid the use of a sense resistor (shunt), which usually produces an undesirable extra voltage drop. The comparator can be monitored by a microcontroller. In case of an overload, the software can initiate suitable countermeasures (PWM regulation, alarm, emergency stop etc.). It is also conceivable to connect the comparator output directly to the gate of the MOSFET, in order to immediately cut off the transistor in case of a short circuit.

Short-Circuit Protection With A MOSFET Circuit Diagram

Friday, October 4, 2013

Video Tracer Circuit Diagram

This circuit was designed as an aid to installers and maintainers of video systems. It is basically a video sync separator (IC1) followed by a LED and buzzer driver (IC2, Q1 & Q2). In use, the device is connected to a video cable and if there is video present, the LED will flash at about 10Hz. If there is no video, the LED flashes briefly every couple of seconds. A buzzer can also be switched in to provide an audible indication. The buzzer is particularly useful when tracing cabling faults or trying to find a correct cable amongst many, where it is difficult to keep an eye on the LED.

Another use for the buzzer option is to provide a video fault indication. For example, it could be inserted in bridging mode, with switch S1 in high impedance mode (position 2) across a video line and set to alarm when there is no video present. If someone pulls out a cable or the video source is powered off, the alarm would sound. IC1 is a standard LM1881 video sync separator circuit and 75Ω termination can be switched in or out with switch S1a. The other pole of the switch, S1b, turns on the power. The composite sync output at pin 1 is low with no video input and it pulses high when composite sync is detected.

Circuit diagram:
video-tracer-circuit-for-trouble-shooting1

video-tracer-circuit-for-trouble-shooting1

Video Tracer Circuit Diagram

These pulses charge a 100nF capacitor via diode D1. When there is no video at the input, oscillator IC2b is enabled and provides a short pulse every couple of seconds to flash the LED. The duty cycle is altered by including D2, so that the discharge time for the 10μF capacitor is much shorter than the charge time. The short LED pulse is used as a power-on indicator drawing minimal average current. When video is present at the input, IC2b is disabled and IC2d is enabled. The output of IC2d provides a 10Hz square wave signal to flash the LED. The buzzer is controlled by switch S2. In position 2 the buzzer will sound when there is video at the input and in position 1 the buzzer will sound when there is no video at the input.

Author: Leon Williams - Copyright: Silicon Chip Electronics

Thursday, October 3, 2013

1993 VW Passat Electrical Circuit Diagram


1993 VW Passat Electrical Circuit Diagram

The Part of 1993 VW Passat Electrical Circuit Diagram: automatic control unit, fuse/relay panel and
emergency lights, fuse/relay panel and fresh air blower switch, Engine control module and ignition coil, console switch, power windows, ABS control unit and ABS hydraulic unit, fuse relay panel and instrument cluster, and taillight, fuse/relay panel and headlight switch, automatic sol, fuse/relay panel and ignition switch, Engine control module.

Monday, September 23, 2013

IR Remote Control Tester Circuit Diagram

Here’s a simple, low cost, and easy to construct infrared remote control tester. The tester is built around an easily available infrared receiver module (TSOP 1238).

Circuit Diagram:

IR Remote Control Tester Circuit Diagram

Normally, data output pin 3 of the IR receiver module is at a high level (5 volts)and as such driver transistor T1 is in cut-off state. Whenever the IR receiver module receives a valid (modulated) infrared signal, its data output pin goes low in synchronism with the received infrared bursts. As a result, transistor T1 conducts during negative pulse period and the.LED blinks to indicate reception of signals from the remote such as TV remote control. A miniature active buzzer is connected at the collector of transistor T1 for audio indication.

The 5V DC for energizing the circuit is directly derived from the 230V AC mains supply. Unlike the conventional resistive voltage divider, a capacitive potential divider is used here, which does not radiate any heat and makes the tester quite compact. Another advantage of this tester is no false triggering due to the ambient light or electronic ballast-operated tubelights. A suggested enclosure for the circuit is shown in Fig. 2.

Author : T.K. Hareendran : Copyright :Electronics For You September 2002

Wednesday, September 11, 2013

Switch ON OFF Touch or with Push Button Circuit Diagram

Here we have three choices, with which we can make electronic switches that use our touch or pressing (push button). We thus exploit the very big resistance of entry, that present the gates CMOS. In the fig.1 we have two gates NAND or NOR (IC1), connected as R-S flip-flop. Just as we press the switch S1, the exit 3 it becomes [H], even it is maintained in this situation.

To change the situation, it should we press switch S2. Now exit 3, takes price (L), reversely exit 4 becomes (H). In order to we maintain the situation that we want, we can connect at parallel with the corresponding switch, a capacitor C=100nF. This entry will always drive the corresponding exit to logic (L), immediately afterwards the benefit of supply to the circuit.

Switch ON-OFF Touch or with Push Button Schematic

Switch ON-OFF Touch or with Push Button Schematic

In the fig. 2, we have a circuit of inverter CMOS, in the entry of which is applied logic situation (H), from the resistance R, which the other end of, is in the supply. Exit 2 has situation (L).

When we press switch S2, in the entry of 3 IC2, we have situation (L), this it goes to the ground, the exit now becomes (H). This situations are maintained as long as we keep pressed switch S2 and they change immediately hardly the touch. If we want opposite logic operation then it will be supposed we connect the resistance R, in the ground and switch S2, in the supply. The same logic we will have if we replace gate IC2, with a gate NAND or NOR, as it appears in the fig. 3, the result is the himself.

Because the situation in the case of fig.1 and 3, does not remain constant and change when we pull our finger , in order to him we retain, it should we connect a J-K or D flip-flop as T, after the IC2 and IC3. Thus the flip-flop, will change situation, each time where we will touch the switch or will touch the contacts and him it will retain.

All the switches can be replaced with contacts, it is enough we replace also resistances R with the price of 10MΩ. The Resistances R when we use pressing switches can are, from 100KΩ until 1MΩ. Because when we use contacts instead of switches, the noise can turn on the gates of fig. 2 and 3, then can place a capacitor 100nF, parallel with the contacts.[via]

Monday, September 2, 2013

Audio Amplifier with High Clarity Circuit

Circuit Diagram

Description

The heart of the circuit is TDA7294 which acts as an amplifier the right and left input feded from the pre amplifier circuit is amplified after passing through the noise filter which contains an RC circuit, the volume is controlled by the variable resistor 47k. and the automatic gain control is provided by the operational amplifier circuit opp amp IC249 For both right channel and left channel., the speaker used is an 8 ohms 40 watts speaker.

Source - http://www.electronguide.com/circuits_pages/AudioAmplifier.html

Monday, August 5, 2013

Overload Speaker Protection Circuit Diagram

Overload Speaker Protection Circuit Diagram input is taken from the terminal loudspeaker or amplifier output jacks. If the right channel is large enough to charge C1 to a potential which exceeds the breakdown voltage of the emitter of Ql, a voltage pulse appears in R7. Similarly, if the left channel signal is large enough to charge C2 to a voltage that is greater than the breakdown voltage of the emitter of Q2 `, a pulse appears in R7. The pulse triggers in R7 5CRI. A door sensitive SCR (LGT less than 15 RNA or IGT is the gate-trigger current) that locks in a conducting state and energizes Ryl. The action of the relay will interrupt the speaker circuit. and silence follows you must alert on the problem.

Overload Speaker Protection Circuit Diagram

Overload Speaker Protection Circuit Diagram

Reduce the volume on your amplifier, then press and release 51 to reset the circuit and restore normal operation. The circuit can be set to go off at any level of 15 watts RMS to 150. To calibrate . deliberately over-power signal at the entrance of the right speaker protection and adjust R3 until RY1 boosts. Do the same with the left channel, this time adjusting R4. The circuit is now calibrated and ready employment.

Saturday, August 3, 2013

MOUSE REPELLENT ELECTRONIC CIRCUIT DIAGRAM

MOUSE REPELLENT ELECTRONIC CIRCUIT DIAGRAM

When the circuit at its close state, the IC will control the buzzer time using the resistor and capacitor. The buzzer sounds like alarm in the different frequencies.

Resistor R1 : 1.8k ohm
Resistor R2 : 1k ohm
Resistor R3 : 5.6k ohm
Resistor R4 : 480 ohm
Capacitor C1 : 2.2 nF
Polar Capacitor C2 : 0.022uF/6V
IC1 timer : NE555
Speaker SP1 : Tweeter 8 ohm
Power supply : 5V

Friday, August 2, 2013

Frequency Tone Decoder Circuit Using TC9400 FVC

Another application of FVC (frequency-to-voltage converter) is tone/frequency decoder. This circuit is used to determine the frequency band of an oscillation signal. This circuit is used in many application like determines the frequency band in the signal and remote control where the frequency band corresponds to a different command. This circuit uses TC9400 F/V converter to convert the frequency to voltage because the frequency must be converted to proportional analog voltage before can be detected. This is the figure of the circuit;

Beside TC9400 F/V converter, this circuit also uses the quad comparators. It used to detect when the frequency limits is exceeded by the voltage (frequency). The frequency is indicated by the logical “1″ at any of the five output. [Circuit diagram source: Microchip Application Note]

Monday, July 29, 2013

Toyota 4runner Hilux Surf Wiring Diagram Electrical System Circuit

Alternator Wiring Diagram on Schematic And Wiring Diagram Here Source Autolib Diakom Ru

Schematic And Wiring Diagram Here Source Autolib Diakom Ru.

Alternator Wiring Diagram on Volkswagen Corrado Wiring Diagram And Electrical System Schematics 94

Alternator Wiring Diagram on Volkswagen Corrado Wiring Diagram And Electrical System Schematics 94

Volkswagen Corrado Wiring Diagram And Electrical System Schematics 94.

Alternator Wiring Diagram on Ford Taurus Wiring Diagram And Electrical System Circuit 90

Alternator Wiring Diagram on Ford Taurus Wiring Diagram And Electrical System Circuit 90

Ford Taurus Wiring Diagram And Electrical System Circuit 90.

Alternator Wiring Diagram on Honda Shadow Vt1100 Wiring Diagram And Electrical System

Alternator Wiring Diagram on Honda Shadow Vt1100 Wiring Diagram And Electrical System

Honda Shadow Vt1100 Wiring Diagram And Electrical System.

Alternator Wiring Diagram on Circuit Wiring Diagram For 2007 Nissan 350z Coupe Charging And

Alternator Wiring Diagram on Circuit Wiring Diagram For 2007 Nissan 350z Coupe Charging And

Circuit Wiring Diagram For 2007 Nissan 350z Coupe Charging And.

Alternator Wiring Diagram on Information About Toyota Corolla Wiring Diagram And Harness H Ere

Alternator Wiring Diagram on Information About Toyota Corolla Wiring Diagram And Harness H Ere

Information About Toyota Corolla Wiring Diagram And Harness H Ere.

Alternator Wiring Diagram on Peugeot 106 Wiring Diagram Electrical System Circuit Circuit

Alternator Wiring Diagram on Peugeot 106 Wiring Diagram Electrical System Circuit Circuit

Peugeot 106 Wiring Diagram Electrical System Circuit Circuit.

Alternator Wiring Diagram on Toyota 4runner Hilux Surf Wiring Diagram Electrical System Circuit 06

Alternator Wiring Diagram on Toyota 4runner Hilux Surf Wiring Diagram Electrical System Circuit 06

Toyota 4runner Hilux Surf Wiring Diagram Electrical System Circuit 06.

Alternator Wiring Diagram on 1998 Nissan Maxima Wiring Diagram And Electrical System Circuit

Alternator Wiring Diagram on 1998 Nissan Maxima Wiring Diagram And Electrical System Circuit

1998 Nissan Maxima Wiring Diagram And Electrical System Circuit.

Alternator Wiring Diagram on Wiring 12v Marine Tachometer Diesel Alternator Instructions How To

Alternator Wiring Diagram on Wiring 12v Marine Tachometer Diesel Alternator Instructions How To

Wiring 12v Marine Tachometer Diesel Alternator Instructions How To.

Friday, July 5, 2013

Simple 600W Audio Amplifier Circuit Diagram

The 600W Audio Amplifier Circuit Diagram is based around {LM4702}manufactured by NATIONAL semiconductors&{MJ11029-MJ11028} by ON semiconductors It is a high fidelity audio power amplifier. Designed for demanding consumer and pro-audio applications. You can also use this circuit with AV receivers, Audiophile power amps, Pro Audio High voltage industrial applications etc Amplifier output power maybe scaled by changing the supply voltage and number of output devices. The circuit includes thermal shutdown circuitry that activates when the die temperature exceeds 150°c. CIRCUIT’s mute function, when activated, mutes the input drive signal and forces the amplifier output to a quiescent state.

Simple 600W Audio Amplifier Circuit Diagram

Simple 600W Audio Amplifier Circuit Diagram

Power:
Maximum Output power @ 8ohms : 300watt
Absolute max power supply voltage :±38V to ±40V
Recommended power supply voltage :±30V to ±35V

Sunday, April 21, 2013

Bass Booster Circuit

Increase the bass output of your present instrument at modest cost!

Bass Boost is todays sound... whether its the driving, gut-vibration pulsation of disco, or the solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound without running out and buying an all-new expensive piece of equipment is to use a Bass Booster between your guitar, electronic organ or what-have-you, and the instrument amplifier.

A bass booster strips the highs from the instruments output signal and amplifies low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, the bigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt transistor radio battery. It can be assembled on a small printed board or on a veroboard using point to point wiring. The booster connects between your instrument and its amplifier through two standard RCA Jacks.

Circuit Diagram:

Bass Booster Circuit

Bass Booster Circuit Diagram

Parts:
P1 = 50K
P2 = 100K
R1 = 22K
R2 = 470K
R3 = 47K
R4 = 10K
R5 = 470R
R6 = 1K
Q1 = 2N2222
C1 = 2.2uF-25v
C2 = 100nF-63v
C31 = 00nF-63V
C4 = 3.3uF-25v
C5 = 470uF-25v
D1 = 5mm. Red Led
Q1 = 2N2222
B1 = 9v Battery
J1 = RCA Audio Input Socket
J2 = RCA Audio Output Socket
S1 = On-Off Switch

Using Bass Booster:

Connect your electronic guitar or other electronic instrument to input jack J1; Connect output jack J2 to your instruments amplifiers normally-used input. With power switch S1 off, key S2 so the instrument feeds directly to the instrument amplifier. With P2 set full counter-clockwise (Off), turn power switch S1 on, key S2 once, and advance P2 for the desired Bass Boost level. To cut back to natural sound just stomp down on S2 and key the Bass Booster out. Dont worry about leaving power switch S1 on for several hours of a gig. The circuit pulls less than 1mA from the battery, so battery will last many, many months.

source :http://www.ecircuitslab.com

Saturday, April 13, 2013

100 Watt Power Amplifier Circuit With IC TDA7294

Power Amplifier TDA7294 is a power amplifier with IC Power Amplifier is a mono 100W Class AB operation of OCL.

The power provide circuit. Positive, bad, and ground. Usually, we use the power supply circuit to + /-25V to + /-35V at 100W RMS shall be used to warmth sufficiently.

After many individuals have already made the TDA7294 as I comprehend, with a sound quality that's the very gods or Hi-End itself.

Several days ahead of the member’s PM to me announcing that I had an amplifier the utilization of IC TDA7294 to have extra of the same. Higher energy. And low warmth.

Achieved by rising the voltage elevating circuit For the more, it way high energy and excessive heat up. Today I have come throughout. I use IC TDA7294 circuit at the time.

In-Home Use amplifier circuit is a Class G amplifier with low energy consumption, ensuing within the loss of a 20V DC power less.

And when you’re driving a excessive-power random get entry to is celebration to a rhythm. Principles to do it. I took out a contributorship you are in a position to do is try to build up slightly.

We offers PCB each top and backside side for you.

Friday, April 12, 2013

How to Make a Simple Timer Circuit Using IC 555

A timer is a device which produces a delay period after which an external connected electrical load is triggered. The produced time delay is normally adjustable and the user has the freedom to set the time period as desired. There are many ways of making simple timer circuits using different ICs and discrete components; here we discuss one such circuit using the ubiquitous IC 555.

The IC 555 is a pretty common electronic part among the electronic enthusiasts and is also very popular due to the involved simple configurations and low component count.

The two popular multivibrator modes of operation that’s associated with this IC are the astable mode, and the monostable mode. Both of these are useful configurations and have plenty of different applications.

For the present design we incorporate the second mode of operation, which is the monostable mode.

In this mode of operation the IC is configured to receive a trigger externally, so that it’s output changes state, meaning if with reference to the ground if the output of the IC is zero, then it would become positive as soon as the trigger (momentary) is received at its input terminal.

This change in its output is sustained for a certain period if time, depending upon the external time determining components. Normally the time determining components are in the form of a resistor and a capacitor which together determine or fix the time period for which the IC output would hold its “high” position.

By changing either the value of the capacitor or the resistor, the timing can be altered as desired. The above time fixing components are termed as the RC component.

The figure shows a very straightforward design where the IC 555 forms the central controlling part of the circuit. As discussed in the above section, the IC is in its standard monostable mode.

Pin #2 receives the external timing trigger from a push-to-ON switch. Once this switch is pushed, the circuit pulls its output to a positive potential and holds it until the predetermined time delay lapses.

The entire circuit can be built over a small piece of general PCB and housed inside a neat looking plastic enclosure along with the battery.

The output may be ideally connected to a buzzer for receiving the warning alarm after the set time lapses.

Parts List

R1, R4 = 4K7,

R2 = 10K,

R3 = 1M pot,

C1 = 0.47uF,

C2 = 1000uF/25V,

C3 = 0.01uF,

IC1 = 555,

Bz1 = Piezo Buzzer,

Push Button = push to ON switch

A circuit design requested by Mr.Bourgeoisie:

Tuesday, April 9, 2013

Cell Phone Battery Meter Circuit 3 6 Volt

This is a circuit for charger that is is a similar circuit to the above and provides a 4 LED bar graph indicating the voltage of a common 3.6 volt Lithium – Ion recharable cell phone battery. The reference voltage is provided by a TL431 programmable voltage source which is set to 3.9 volts where the TL431 connects to the 1K resistor. The lower reference for the LED at pin 14 is set with the 5K adjustable resistor. This is the figure of the circuit;

The programmed voltage of the TL431 is worked out with a voltage divider (10K 5.6K). The adjustment terminal or junction of the two resistors is always 2.5 volts. So, if we use a 10K resistor from the adjustment terminal to ground, the resistor current will be 2.5/10000 = 250uA. This same current flows through the upper resistor (5.6K) and produces a voltage drop of .00025 * 5600 = 1.4 volts. So the shunt regulated output voltage at the cathode of the TL431 will be 2.5 + 1.4, or 3.9 volts.

Working out the LED voltages, there are three 390 ohm resistors in series with another adjustable (5K) resistor at the bottom. Assuming the bottom resistor is set to 2K ohms, the total resistance is 390+390+390+2000 = 3170 ohms. So, the resistor current is the reference voltage (3.9) divided by the total resistance, or about 3.9/ (390 + 390 + 390 + 2000) equals 1.23 mA. This gives us about .00123*2000= 2.46 volts for the bottom LED, and about .00123*390 = .48 volts for each step above the bottom. So, the LEDs should light at steps of 2.46, 2.94, 3.42, and 3.9. A fully charged cell phone battery is about 4.2 volts. You can adjust the 5.6K resistor to set the top voltage higher or lower, and adjust the lower 5K resistor to set the bottom LED for the lowest voltage. But you do need a 6 to 12 volt or greater battery to power the circuit.

Mini High Voltage Generator Circuit

Here’s a project that could be useful this summer on the beach, to stop anyone touching your things left on your beach towel while you’ve gone swimming; you might equally well use it at the office or workshop when you go back to work. In a very small space, and powered by simple primary cells or rechargeable batteries, the proposed circuit generates a low-energy, high voltage of the order of around 200 to 400 V, harmless to humans, of course, but still able to give a quite nasty ‘poke’ to anyone who touches it.

Quite apart from this practical aspect, this project will also prove instructional for younger hobbyists, enabling them to discover a circuit that all the ‘oldies’ who’ve worked in radio, and having enjoyed valve technology in particular, are bound to be familiar with. As the circuit diagram shows, the project is extremely simple, as it contains only a single active element, and then it’s only a fairly ordinary transistor. As shown here, it operates as a low-frequency oscillator, making it possible to convert the battery’s DC voltage into an AC voltage that can be stepped up via the transformer.

Using a centre-tapped transformer as here makes it possible to build a ‘Hartley’ oscillator around transistor T1, which as we have indicated above was used a great deal in radio in that distant era when valves reigned supreme and these was no sign of silicon taking over and turning most electronics into ‘solid state’. The ‘Hartley’ is one of a number of L-C oscillator designs that made it to eternal fame and was named after its invertor, Ralph V.L Hartley (1888-1970). For such an oscillator to work and produce a proper sinewave output, the position of the intermediate tap on the winding used had to be carefully chosen to ensure the proper step-down (voltage reduction) ratio.

Here the step-down is obtained inductively. Here, optimum inductive tapping is not possible since we are using a standard, off-the-shelf transformer. However we’re in luck — as its position in the centre of the winding creates too much feedback, it ensures that the oscillator will always start reliably. However, the excess feedback means that it doesn’t generate sinewaves; indeed, far from it. But that’s not important for this sort of application, and the transformer copes very well with it.

The output voltage may be used directly, via the two current-limiting resistors R2 an R3, which must not under any circum-stances be omitted or modified, as they are what make the circuit safe. You will then get around 200 V peak-to-peak, which is already quite unpleasant to touch. But you can also use a voltage doubler, shown at the bottom right of the figure, which will then produce around 300 V, even more unpleasant to touch. Here too of course, the resistors, now know as R4 and R5, must always be present. The circuit only consumes around a few tens of mA, regardless of whether it is ‘warding off’ someone or not! If you have to use it for long periods, we would however recommend powering it from AAA size Ni-MH batteries in groups of ten in a suitable holder, in order not to ruin you buying dry batteries.

Circuit diagram:

mini-high-voltage-generator-circuit

Warning!
If you build the version without the voltage doubler and measure the output voltage with your multimeter, you’ll see a lower value than stated. This is due to the fact that the waveform is a long way from being a sinewave, and multimeters have trouble interpreting its RMS (root-mean-square) value. However, if you have access to an oscilloscope capable of handling a few hundred volts on its input, you’ll be able to see the true values as stated. If you’re still not convinced, all you need do is touch the output terminals...

To use this project to protect the handle of your beach bag or your attachecase, for example, all you need do is fix to this two small metallic areas, quite close together, each connected to one output terminal of the circuit. Arrange them in such a way that unwanted hands are bound to touch both of them together; the result is guaranteed! Just take care to avoid getting caught in your own trap when you take your bag to turn the circuit off!

Source by : Streampowers

High CMR Isolation Amplifier Circuit

transients that are generated by the switching of the inverter transistors. Here’s the figure of the design circuit;

Developed as a compact low-cost solution for just this type of design problem, the HCPL-7800 High CMR Isolation Amplifier allows designers to sense current in extremely noisy environments while maintaining excellent gain and off set accuracy. It exhibits outstanding stability over both time and temperature, as well as unequaled common-mode transient noise rejection (CMR). To achieve such a high level of performance, the HCPL) analog-to-digital converter (-7800 combines several different technologies, including a state-of-the-art sigma-delta (ADCm standard-cell), chopper-stabilized internal amplifiers, a fully differential circuit topology fabricated on a 1 CMOS process, an edge-triggered level-sensitive data encoder/decoder circuit, a high-efficiency, high-speed AlGaAs LED, an advanced photo-detector noise shield, and an efficient “light-pipe” packaging technology. The HCPL-7800 is available in a small 8-pin DIP package, making it the world’s smallest isolation amplifier.

Sunday, April 7, 2013

High Voltage AC Calibrator Circuit Using Op Amp

This a application circuit for calibration. This circuit is called high voltage AC calibrator circuit. In another dimension in sine wave oscillator design is stable control of amplitude. This is the figure of the circuit.

In this circuit, not only is the amplitude stabilized by servo control but voltage gain is included within the servo loop. A transformer is used to provide voltage gain within a tightly controlled servo loop. A voltage gain of 100 is achieved by driving the secondary of the transformer and taking the output from the primary. A current sensitive negative absolute value amplifier composed of two amplifiers of an LF347 quad generates a negative rectified feedback signal. This is compared to the LM329 DC reference at the third LF347 which amplifies the difference at a gain of 100. The 10 μF feedback capacitor is used to set the frequency response of the loop.

The output of this amplifier controls the amplitude of the LM3900 oscillator thereby closing the loop. As shown the circuit oscillates at 1 kHz with under 0.1% distortion for a 100 Vrms (285 Vp-p) output. If the summing resistors from the LM329 are replaced with a potentiometer the loop is stable for output settings ranging from 3 Vrms to 190 Vrms (542 Vp-p!) with no change in frequency. If the DAC1280 D/A converter shown in dashed lines replace the LM329 reference, the AC output voltage can be controlled by the digital code input with 3 digit calibrated accuracy. [Schematic diagram source: National Semiconductor, Inc]

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