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8 Watts Audio Amplifier (TDA2003)
Nice small audio amplifier which use only few parts to give good quality sound. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp. Although not perfect, this amplifier does have a wide frequency response, low harmonic distortion about 1.5%, and is capable of driving an 8 ohm speaker to...
1W stereo Headphone Amp (TDA2822)
A stereo power amp designed for use in portable players and radios. A 3V supply can be used to drive headphones providing 20mW in 32 Ohms per channel.
The discrete-gate up/down-counter design has the unusual property of freezing, or saturating, when it reaches its lowest count in the down-count mode or its highest count in the count-up mode instead of rolling over and resetting as do most counters. This property proves especial!y useful in position-control systems. For example, you wouldn"t...
This generator will supply sine, triangular, and square waves from 2Hz to 20kHz. This complete test instrument can be plugged into a standard 110 Vac line for power. VoVT will be up to ±25 V (50 V pk-pk across loads as small as 10 0 (about 2.5 A maximum output current). Capacitor working voltages should be greater than 50 V de and all...
Power Mosfet Inverter
This inverter can deliver .high-voltage ac or de, with a rectifier and filter, up to several hundred volts. The secondary and primary of T1-a 12.6 to 440 V power transformer, respectively-are reversed; e.g., the primary becomes the secondary and the secondary becomes the primary. Transistors Q1 and Q2 can be any power FET.
Phase Control Circuit
The most elementary application is a half-wave control circuit. The thyristor is acting both as a power control device and as a rectifier, providing variable power to the load !luring the positive half cycle and no power to the load during the negative half cycle. The circuit is designed to be a two terminal control which can be inserted in...
Here is a simple tachometer circuit for use with a hand-held DVM or portable chart recorder. A novel feature is that the source frequency pulse/rev rate can be directly set on a ten-turn potentiometer to provide a convenient calibration of one V per 1000 rev/min. This is particularly useful when measuring a shaft or engine speed by sensing...
Stereo Led Vu Meter
This circuit provides a cheap alternative to the LM3915 series LED displays. The meter relies on a square-wave oscillat
Analog Tachometer Readout
The analog display consists of a frequency/voltage converter (IC12) and bar-graph segment drivers IC10 and IC11.
Simple Staircase Generator
U2 is a decade counter /divider, Ul is used as a switch debouncer. For a self-generating system, connect a resisor
Wide-Range Crystal Oscillator Circuit
A circuit using one 7400 TTL10 can use crystals of the fundamental type, from 1 to about 13 MHz. Output is rich in harmonics,
Audio splitter amplifier circuit with TL084
The three-channel amplifier output distribution uses a single TL084. The first step is to capacitive coupling with a p. 1.0 ~ electrolytic capacitor. The entries are railways Vee Y2 or 4.5 V. This allows using a single 9 V power supply A voltage gain of 10 (1 M ohm ohm/l00 k) is obtained in the first stage, and the other three floors are...
Automatic Audio level control with NE570
The NE570 can be used to make a high performance compressor FTA, except that the rectifier is connected to the input. This makes gain inversely proportional to the input level so that a drop of 20 dB input level will produce an increase of 20 dB gain. The output remains at a constant level. As shown, the circuit will maintain an output level of...
Lithium battery indicator
State-of-Charge indication of-a sloping-voltage discharge can be used as a state-of-charge indicator. A typical voltage comparator circuit that gives a visual indication of state-of-charge is shown.
1W Linear FM Booster
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 voltage can boost the distance but the transistors will be burned much earlier than usual.!...
2 Watts FM transmitter
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, L2= 1 turn - 10mm diameter. R9 trimmer controls the modulation gain. The tunning is easy...
FM surveillance BuG Transmitter
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 to feed in 9-12 Volts.
TV and FM jammer schematic
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 Capacitor is 6-10pf air capacitor and the transistor used here is the 2n2222.
0-30 Volts / 2,5A Variable Power Supply
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 great stability at voltage changes.
Passive subwoofer filter
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.
Simple Coil-less AM receiver
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.
Free energy collector circuit
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 should be more than 150 feet long wire, placed horizontally as high as you can for best...
PAL Colour Encoder (TEA2000-V1)
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 applied to the resultant luminance and chrominance levels.
40 Watt Audio power Amplifier LM3876
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 continuously into 8ohm load, and is fully protected using established techniques. The...
Waveform Generator with ICL 8038CCPD
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 accomplished with an external voltage and the frequency can be programmed digitally by resistors or...
Bomb Proof 150 Watt MOSFET Power Amplifier
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. Thermally, the MOSFET has an advantage over the bi-polar transistor. As a bi-polar...
0-60sec start-stop timer with 555
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. By simple modifications it is possible to adjust the maximum time and the timing scale,...
6-17 MHz SW reciever
Its very simple as It uses only 3 transistors 2n2222.The Coils can be altered to change the range of reception by lowering or highering the frequency.
Double oscillator metal detector
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 working closely together) is detected by the diode and fed to the headphone amplifier and the...
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
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