FM Radio jammer

john January 13, 2010 117 Comments
Description. Circuit shown here can be used to jam FM radios in its vicinity. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. Working principle of the circuit is very simple and straight forward. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. Jammer circuits like this are illegal in many countries and you must assemble this circuit on your own responsibility. This circuit is intended only...
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Sweep Frequency Generator

john March 28, 2011 3 Comments
Sweep-Frequency Generator The working of a sweep-frequency generator is explained in the article below. The working and block diagram of an electronically tuned sweep frequency generator and its different parameters are also explained. Related Article SIGNAL GENERATORS A sweep frequency generator is a type of signal generator that is used to generate a sinusoidal output. Such an output will have its frequency automatically varied or swept between two selected frequencies. One complete cycle of the frequency variation is called...
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Signal Generators

john February 22, 2011 1 Comment
Signal Generators In this article, the detailed explanation of a signal generator is given. The principles of signal modulation, the block diagram of an AM signal generator and the measures needed to achieve a stable frequency output is explained below. RELATED ARTICLE SWEEP FREQUENCY GENERATOR Like an oscillator, a signal generator is also a  source of sinusoidal signals. The main difference between a signal generator and an oscillator is that  a signal generator is capable of modulating its sinusoidal...
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Selection Of An Oscillator

john March 28, 2011 No Comments
RELATED ARTICLE VOLTAGE CONTROLLED OSCILLATOR (VCO) SWEEP-FREQUENCY GENERATOR BEAT FREQUENCY OSCILLATOR (BFO) WIEN BRIDGE OSCILLATOR PHASE SHIFT OSCILLATOR Here are the parameters that are to be noted while selecting an oscillator for a particular application. Frequency Range. The oscillator selected for a particular application should be ca­pable of supplying an output signal whose upper and lower frequency limits exceed those required by the application. Power and/or Voltage. The oscillator selected for a particular application should be capable of generating...
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Negative Resistance Oscillators

john March 28, 2011 2 Comments
In this article, the working of a negative resistance oscillator is explained along with its types-dynatron and tunnel diode oscillator. The tunnel diode oscillator characteristics and circuit is also explained in detail. Related Articles VOLTAGE CONTROLLED OSCILLATOR (VCO) SWEEP-FREQUENCY GENERATOR BEAT FREQUENCY OSCILLATOR (BFO) WIEN BRIDGE OSCILLATOR PHASE SHIFT OSCILLATOR TRANSISTOR PHASE SHIFT OSCILLATOR Negative resistance oscillators make use of negative resistance elements such as tetrodes, tunnel diodes, uni junction transistors etc. There are two types of negative resistance...
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Beat Frequency Oscillator (BFO)

john March 4, 2011 2 Comments
Beat Frequency Oscillator (BFO) Related Articles OSCILLATOR OPERATION TUNED BASE OSCILLATOR PHASE SHIFT OSCILLATOR COLPITTS OSCILLATOR Use the link OSCILLATORS to see all the articles including the working of oscillators, frequency stability, types and so on. The beat frequency oscillator (BFO) is used to produce a vari­able frequency output in the audio-frequency (AF) range. BFO is used  when the need comes to cover a very large frequency range with a single dial rotation as it can produce a very...
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Wien Bridge Oscillator

john August 14, 2017 20 Comments
Wein Bridge Oscillator is one of the mosttypesular type of oscillators used in audio and sub-audio frequency ranges (20 – 20 kHz). This type of oscillator is simple in design, compact in size, and remarkably stable in its frequency output. Furthermore, its output is relatively free from distortion and its fre­quency can be varied easily. However, the maximum frequency output of a typical Wien bridge oscillator is only about 1 MHz. This is also, in fact, a phase-shift oscillator....
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Transistor Phase Shift Oscillator

jojo January 29, 2014 3 Comments
RC Phase shift oscillator. RC phase shift oscillator or simply RC oscillator is a type of oscillator where a simple RC network (resistor-capacitor) network is used for giving the required phase shift to the feedback signal. In LC oscillators like Hartley oscillator and Colpitts oscillator an LC network (inductor- capacitor network) is used for providing the necessary positive feedback. The main feature of an RC phase shift oscillator is the excellent frequency stability. The RC oscillator can output a...
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Phase shift oscillator

FET Phase Shift Oscillator

jojo July 24, 2018 1 Comment
What is a FET Phase Shift Oscillator? A phase shift oscillator is a circuit that produces sign waves. The output is fed back to the input which changes the ‘phase’ of the waves.  The phase shift increases with frequency and can reach a maximum of 180 degrees. Phase shift oscillators have a wide range of applications which are detailed further below. We select the so-called phase shift oscillator as a first example as it exemplifies very simply the principles set...
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Audio Oscillators

jojo March 28, 2011 1 Comment
An introduction to Audio Oscillators also known as RC Oscillators So far, we have considered the oscillators which use L-C tuned circuit that causes a phase shift of 180° due to inductive or capacitive coupling in addition to a 180° phase shift produced by the transistor itself. The oscillators employing L-C elements, called the L-C oscillators, are very popular for generating high frequency oscillations but they cannot be employed for generation of low frequency oscillations as they become too...
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