Top Circuits Page 56
- Page 56
-
This circuit uses an MC1373 to form a TV video modulator. The coil and capacitor connected between pins 1 and 2 should be selected to have a parallel resonance at the carrier frequency of the desired TV channel...
-
-
The circuit needs that the VGA card sends out the video signal the the RGB format compatible with PAL or NTSC standard video timings. This is accomplished with right VGA to TV driver...
-
Desheng 1012 12-band FM, MW, SW, TV sound radio circuit diagram as follows: ..
-
The VTG-01 is designed to display user defined text over a composite video signal. This is useful in a multitude of different applications such as adding titles to home movies and adding custom text to security videos. Text can be displayed in different....
-
Want to add video to your next project? This device uses a PIC16F819 and not much else. Getting 20 characters to a line is possible by using the SPI port to generate video. Neat trick, eh? The character set is limited to upper case and a few punctuation....
-
When you use microcontrollers in your designs, sometime you face a problem how to show user required data. Several LEDs, 7 segment display or LCD module can be solution. But if you must show a lot of information simultaneously, it can be difficulty. Large....
-
-
The cross compiler works on any host supported by GNU tools (Solaris, GNU/Linux, FreeBSD, HP/UX, MacOS X, Windows,...)...
-
The 8052.com SBC is a single-board computer designed to be both useful and instructive in illustrating certain concepts commonly encountered in 8052-based development...
-
According to the MSC1210 datasheet, you will perform an external reset by taking RST pin high for two tOSC periods as this stops device operation, crystal oscillation, causes all digitall pins to be pulled high from that point and then followed by taking the....
-
74hc573 is used to store data so that the previous content on SS is not vanish when we disable LE pin. T0 select the proper latch 74hc238, 3x8 decoder is used. And to convert BCD into decimal, 74ls48 converter is used. Note that latches U1 to U4 are....
-
The circuit shown below is a basic latching circuit consisting of a quad 2-input NAND Gate IC. It is configured such that the flip flop circuit U1A and U1B has both its input held at logic "1". Pin 1 is held at logic "1" by the magnetic contact and pin 6 is....
-
-
This bug can be attached to anything from a glider to a pot plant and you can track it with a radio.
Why track a pot plant?
The Beeper is the result of many requests for a mini tracking device and introduces a new world of tracking.
The circuit is very....
-
The circuit consists of three stages, an electret microphone, an audio amplifier and an RF oscillator.
The electret microphone consists of only two parts - a FET transistor and a plastic diaphragm. There is nothing else inside the case. The 3-leaded FET has....
-
Is a 100 to 200 metre (100 to 200yds) device having a very stable performance. It can be used as a hand held microphone or left on a shelf to pick up the sounds in a room.
It has many interesting features. These will be fully described in the article. One....
-
Many times exists the need recording some conversations from a telephone line and this it's relatively easy. If we want however to have the possibility recording from two telephone lines simultaneously in a tape recorder, we needed a circuit as what appears....
-
This circuit is not open for discussion. Although working perfectly, it was experimental. I will answer no emails in regards to this circuit.
If you are looking for a more serious and reliable bug detector, go to the Countersurveillance Monitor article on....
-
Circuit principle: OV9650 processor interfaces include three parts SCCB interface, data output interface and control interface. SCCB interface to play the role of transfer prov..
-
This is a simple Surround Processor with the degital delay method. This audio processor is not using any special function ICs that difficult to get parsonaly, and desined in only general purpose ICs. Of course the Digital Delay Block of A-D, D-A and delay....
-
This surround-sound decoder is based on the "Hafler" principle, first discovered by David Hafler sometime in the early 1970s. The original idea was to connect a pair of speakers as shown in Figure 1, for use as the rear speakers in the surround setup. This....
-
This Adjustable Strobe Light is the bigger brother of the plain old strobe light. This one uses a much more powerful "horse shoe" Xenon tube which produces more light. You can also control the flash rate up to about 20Hz. Do not look directly at the flash....
-
This DC-DC converter ("inverter") needs nothing but unmodified Radio Shack parts. You don`t need to build or wind any coils or transformers. This is a cheap-and-dirty experimenter`s circuit. I tested this and it worked for me, but I disclaim all warranties!....
-
Figure 1 shows a complete circuit for an emergency lamp that operates from a 12V automotive battery. The xenon flash tube requires a 250V-dc anode voltage and a 4-kV trigger pulse. To generate the 250V dc, IC1, a switching regulator controller, and T1, a....
-
Flash slaves are used when you need to supplement one flash unit with one or several more. This slave trigger simply triggers those other units. It does this by "seeing" the first flash (using a phototransistor) and triggering the other flashes a few....
-
This is a mini strobe light. NE555 is used as a self oscillator. The width of output pulse is changed by the variable resister. 25msec means 40Hz. 6m sec means 166Hz. A LED is connected on the output of this oscillator. Therefore LED twinkles from 40Hz to....
-
This model is very simple and charges as long as you hold the pushbutton:..
-
These photoflash, or strobe, capacitors range in value from a hundred microfarads to over a millifarad, with target output voltages above 300V. Traditional strobe capacitor charging methods are either inefficient or require software overhead. The LT3420....
-
This circuit (the Bucciarelli one) is designed to sense a sudden increase in light and does so extremely well. A few of these were actually built and tested and found to not trigger from normal room light. They sometimes malfunctioned if the phototransistors....
-
Disco anyone? Actually, this strobe serves a much more useful purpose then making it look cool when you dance in the dark. You can use it to view fast moving objects, look for craks in PC boards (hold the strobe on the trace side of the board and look from....
-
Cell phones and PDAs are approaching the limit for small form factors, but their feature sets are growing with new functions such as built-in cameras and even video cameras. The initial in-phone cameras were basic, low resolution devices with little in the....
-
This flash circuit is a typical camera flash. ..
-
There is a voltage divider composed of R2 (10M) and R3 (100K) which effectively divides the voltage across C2 by about 100. Also note the ground of C2. It is connected to the inverter ground for reference. I used an LM358 comparator to keep track of the....
-
The circuit uses an IRF740 MOSFET which is rated at a maximum DS V value of 400V. The avalanche voltage is calculated as 3520 1. max DSA VV V. This means that up to about 500V of inductive kickback voltage can develop in the switched coil. More than....
-
EPSON PHOTO 830U printer power circuit It shows EPSON PHOT0 830U printer power supply circuit, which belongs to the switching power supply. In normal operation, the power suppl..
-
Circuit at rest (dark) state operation the electromagnet M current flows, once there is sufficient strength so that light shines on the phototransistor is turned on, that is th..
-
That RF Amplifier is for boosting small fm transmitters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More....
-
This is a nice 2 Watts FM transmitter. It has a Super-Sensitive pre-amplification with BC109 and BC177 with more than 100% signal modulation. The job finish the 2N2219 by Motorola. For the Coils you should use 1mm wire(enameled), L1= 3 turns - 10mm diameter,....
-
The Circuit shown can transmit voice to exceptionally good range. Tune trimmer to hear the signal to your near radio. Frequency range is 88-108 MHz. Max current consumption is 30mA. You can power the bug with a 9Volt Battery, or you can plug a power supply....
-
The Jammer is a very small circuit and can fit inside a small plastic box with 9V battery inside. It can be very illegal if you attach an external antenna so don't. adjust frequency by turning trimmer. It is intended only as a practical joke device. The....
-
This is a high quality power supply with a continuously variable stabilized output adjustable between 0 and 30VDC. the LM 723 is the heart of the power supply which drives the BD137 and then the 2N3055. The circuit provides short circuit protection. And has....
-
The schematic shown, does no need any power supply because is a simple low frequency passive filter. It could be usefull if you want to drive an extra subwoofer from your stereo system...
-
This AM receiver is working perfectly without the need of coils or even a variable capacitor. The LF356 is the basic component. P1 and P2 are the frequency selectors. Use a small telescopic antenna. The stations selectivity is not perfect but is acceptable. ..
-
This circuit converts surrounding radio frequency waves to electric power. It can provide 40 Volts at 10 Watts indefinitely. The output power can be improved playing with the antenna. Placing the antenna near large metal objects gives more power. Antenna....
-
A PAL color encoder and video summer which requires just composite sync and composite blanking inputs, and a 6-bit binary coded input giving the color information. The inputs are organized as 2 bits per primary color with gamma correction automatically....
-
This Circuit is based on the LM3876. A 11-pin plastic package IC with high performance audio power amplifier, an output mute function which can be used to eliminate switch-on and switch-off "thumps" to the loudspeaker load. It is capable of delivering 40W....
-
That circuit is based on a 14-pin DIL IC capable of producing sine, square, triangular, sawtooth and pulse waveforms of high accuracy and stability. The frequency may be selected to be from 0.001Hz to 1Mhz, Frequency modulation and sweeping can be....
-
In my opinion that is the best buildable high power amplifier out there. Quality of sound is just remarkable. This is a real bomb proof amplifier like the best Valve amps. Power supply circuit is also shown. Now lets see why we are going to use MOSFETS.....
-
This timer is ideal for small aplications. Due to its simple structure, its usage and nevertheless its universal character, this mini timer is usable in the most current applications needing time intervals, from some seconds through approximately 60 minutes.....
-
The circuit consists of two oscillators, both working at about 465 kHz. One uses an if transformer and the other uses an inductor (the search coil LI). The oscillators are coupled by a capacitor (10 pF). A beat note (produced if the two oscillators are....
-
This is a 1-amp variable-voltage PSU. It adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment...
-
This PSU has been especially designed for current-hungry ham radio transceivers. It delivers safely around 20Amps at 13.8V. For lower currents, a separate current limiting output, capable of 15ma up to a total of 20A has been added...
-
The circuit is based on IC1, an LTC1430 PWM controller. The current-limiting feature of the IC operates by sensing the voltage across the high-side MOSFET and compares it with a threshold voltage developed across R3...
-
The three major types of current-limit-protection mechanisms are constant, foldback, and hiccup. Hiccup current limit performs the best of the three types; however, the implementation is rather complex. In this scheme, upon detection of an overcurrent event,....
-
The versatile 5 pin L200C regulator offers both voltage and current regulation in a single package. The IC also features thermal shutdown and input over voltage protection up to 60 Vdc. The package is also available as L200CV which has straight pins for....
-
The circuit in Figure 1 shows how a thermistor applies temperature compensation to the circuit`s output-current limit.
The MAX1714`s linear current-limit (ILIM) input range at Pin 6 of IC1 spans 0.5 to 2V, which corresponds to current-limit thresholds of....
-
Figure 1 shows a 5V to 12V boost converter ideal for USB
applications. The converter has a selectable 100mA/
500mA input current limit, allowing the device to be easily
switched between the USB low and high power modes.
Efficiency, shown in Figure 2,....
-
Current-limit switches are virtually ubiquitous in system controls. They provide a safe means for regulating the current delivered to a load circuit. The switches allow the load current to increase to a programmed limit but no higher. This application note....
-
The following are current regulator circuits that can be used to drive light emitting diodes. As always, take time to do some testing before attempting to use these circuits in actual applications...
-
Volt regulators such as the LM708, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be....
-
SN75064 ~ SN75067 is a monolithic, high-voltage, high-current Darlington switch output termination..
-
As shown using MIC5156- is a composition having a current limiting function, and a lot of high output current is turned off may be low with or without regulator switching regulator circuit. S terminal vacant, and the gate - plus a l6 V Zener..
-
MC1411 series of Darlington Drive current internal structure Darlington current driver has a small, consistent, and high reliability parameters, especially for high-voltage,..
-
As shown in Figure is a limiting protection charger. VT transistors and resistors R3 form limiting network. Seen from the figure, the resistor R3 is the base of transistor VT e..
-
The circuit in Figure 1 tests these characteristics. It charges the capacitor under test through 100 k for approximately 1 msec and then discharges it through 10 for approximately 40 nsec. The cycle then repeats. The circuit uses a double-sided copper-clad....
-
When an antenna is attached, (or even if not, in the presence of a strong RF field) the field strength meter has a moving coil meter to indicate relative field strength. The box holds a Schottky diode detector, a DC amplifier, and a meter display. If the....
-
Using a standard PLL circuit, such as the CMOS 4046B with some passive components, is a well-known way to design a clock multiplier. Unfortunately, using a PLL in a digital circuit has two disadvantages: It takes a long time for the circuit to reach a stable....
-
This is basically a high gain amplifier with feedback that causes the LED to flash at a rate determined by the 10u and 330k resistor. Remove one of the transistors and insert the unknown transistor. When it is NPN with the
pins as shown in the photo, the....
-
Transistor Q1, a 2N3563, and its associated components form an oscillator circuit that will oscillate if, and only if, a good crystal is connected to the test clips. The output from the oscillator is then rectified by the 1N4148 signal diode and filtered by....
-
The following circuit enables me to measure inductance of the inductor labeled LX which is the inductance to be measured. The o/p of the circuit is a TTL square wave whose frequency relates to the inductance being measured. The heart of the circuit is the....
-
A differential amp used by the SIM, and it is a completely conventional circuit. This is adjustable by using VR1 to null out any normal variations that the amp might show when there is no distortion or other nastiness in evidence. The second stage is a....
-
An RF probe is used to directly measure the level of RF voltage present at a particular point and is one of the most useful test instrument in the hands of the home brewer. It is normally used with a digital multi meter to indicate the voltage level as dc....
-
The capacitance between the wire and the probe would form a capacitive voltage divider with the probe's input capacitance, and at frequencies significantly higher than the low frequency roll off created by the probe's input capacitance and the probe's....
-
This is a variation on the astable multivibrator. Circuit was recently developed to test for N-mosfets(the power kind e.g irf830). I don?t claim circuit can test all bad mosfets or all fault mosfet conditions. If mosfet is working it will operate in the....
-
The experimenter's pot is a solid state potentiometer using Dallas semiconductor?s DS1869 and National?s LM78L05 two electrolytic capacitor two small push button switch and two optional Molex connector. this project is very useful especially in finding the....
-
The probe described here was designed to be used over the range of several tens of Hz to a couple MHz with currents from a few tens of milliamps to about 10 amps peak-to-peak. Formulae are give which will allow you to create a design suitable for your own....
-
The µCurrent is in many cases also able to improve upon your meters current range accuracy by using your meters more accurate mVDC or mVAC voltage ranges instead to display the DC or AC current. With AC the frequency response extends flat up to 10KHz, but....
-
1 kHz is a commonly used test frequency, and I resolved to see if I could make an inductance meter that uses a 1 kHz test signal at a low level. I also wanted to use a low level test signal so that the test current would have a minimal effect on the....
-
This circuit can be easily powered from a 1.5 volt battery. One characteristic of N type negative resistance devices is that they typically require a very low bias source resistance in order to keep the bias voltage stable within the negative resistance....
-
This circuit as first published in Wireless World September 1975 and subsequently in MECRM. It's built around a TTL quad NOR gate, though CMOS could be used...
-
Bridge circuit contains two resistors lOO-ohm (R3 and R4), and two thermistors (Tl and T2). At room temperature, the resistance of T1 and 1'2 is about 2000 ohms. When they are each heated to 150 ° C by an RNA 10 current, the resistance value decreases to....
-
The detector will sense static charges and free ions in the air. It can be used to indicate the presence of ion emission, high voltage, static electricity, and electrostatic fields. The ground can be an earth ground or a touching metal by your hand...
-
741 op amp can be used as a voltage comparator. Non-inverting input and a zener control source. The reference voltage is 5.1V. R2 can adjust the in-phase input voltage becomes ..
-
ACER PM02 MP4 machine shows voltage status indicator circuit, when there is power red LED lights when entering the work, the green LED lights. ..
-
Chen is in the OP put too amplifying circuit, so that the comb over current feedback loop with input resistance determined current roll, so FET drain current, a gate by the det..
-
This project gives you a fingerprint based attendance system with 8051 microcontroller. The SM630 fingerprint module is used for fingerprint matching. It can store a max of 768 fingerprints. The admin can add/delete records from the PC through the VB....
-
This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally open and normally closed switches and will accommodate the usual input devices such as Foil Tape, Pressure Mats, Magnetic Reed Contacts,....
-
The thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees Celsius. A suitable bead type thermistor can be found in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of temperatures. If using a different....
-
Using Wuxi love core Microelectronics Co., Ltd. H1.9811 single Chan flash control integrated road barricades made of flashing warning lights, HL9811..
-
The gain control element is a Light Dependent Resistor (LDR). These are blessed with a few very useful features for our purposes, one of which is low distortion even at quite high signal levels. Being light activated, all we need is a LED to provide....
-
Repell those repugnent insects from your Garden this Summer with this insect repellant circuit. Designed by Graham Maynard the circuitry consists of a phase locked loop (CMOS 4047) wired as a 22KHz oscillator. The output is amplified by a pair of....
-
A fast electronic fuse designed to operate on 230V AC with an adjustable trip current. When the current through the load exceeds a level determined by the position of the wiper on the 1k wire-wound pot, this circuit cuts off the load immediately. If S1 is....
-
Safety devices like fuses provide protection against excess current, but do nothing for transients and short duration spikes of high voltahe on the power supply lines.This circuit uses the "crowbar" method and provides fast protection against transient....
-
This circuit has proved very useful in keeping away from a terrace or a porch some bats and other nocturnal animals. You can use it for similar or different purposes. The lamp illuminates for a 4-5 seconds delay and stays off about one minute and 15 seconds.....
-
This circuit stores a single morse code message as bits in an EPROM chip, the message is sent to a relay which can key a CW transmitter. The keyer can output either a one-shot message such as "CQ DX DE CALLSIGN", or a continuous message. The continuous mode....
-
The detector circuit shown in Figure 1 (1) is simple and works well, and as shown will not trigger with a 30V RMS signal at 5Hz, but operates in 60ms with 30V DC applied, and in 50mS with a 45V DC supply. This should be sufficient for most applications, and....
-
This is a fun and non-dangeros project for those people who like to throw projectiles magnetically. It simply works by placing a ferromagnetic projectile at one end of a coil and pulsing some power in it. The trick is to switch off power when the projectile....
-
The reader mechanism shown was purchased from All Electronics for $1.50. The unit provides the magnetic head on a spring mechanism along with low level head signal amplifiers and data slicers. Three signal lines comming from the unit provide card presence,....
-
This circuit is for a QRP (low power) antenna tuner, a.k.a. a transmatch, for use in the short wave amateur radio bands from 3-30 Mhz. It allows a wide variety of antennas to be connected to a low power transmitter. When the circuit is properly tuned, the....
-
Almost any receiver covering 540 kHz to 1600 kHz is suitable for broadcast band DX`ing, and there are a lot of them. But the antenna is another matter. If you are new to the hobby, or if you have been having trouble DX`ing those really difficult stations,....
-
This circuit is for a QRP (low power) antenna tuner, a.k.a. a transmatch, for use in the short wave amateur radio bands from 3-30 Mhz. It allows a wide variety of antennas to be connected to a low power transmitter. When the circuit is properly tuned, the....
-
A ground loop in your AV system caused by antenna connection or TV cable is very common if you have your computer connected to the same system. This type of ground loop problem can be solved by using suitable isolation between your AV system and the antenna....