FM Radio Jammer Circuit

Jammer Circuits:

In olden days while we were using analog signal for communication, the jamming circuit was very easy just by producing the high frequency noise signals, but today trend is completely changed in such a way that use of digital devices taken place from analog devices. High frequency signals are not capable to block those signals from reaching the devices, so we need very high frequency signals to block the actual signals from reaching the devices, so jammers are used for blocking the signals. Jammer circuit produces the high frequency signal which will confuse the receiver of particular system from receiving the signal, even though circuit is working properly, user of the system feels that circuit is not working properly. This type of high frequency signal generation through jammer is called noise and the circuit is called jammer because it will mix the main signal with noise signal.

Now let us know about simple FM Radio Jammer Circuit and its working.

FM Radio Jammer Circuit Diagram:


Circuit Diagram of Simple FM Radio Jammer

Circuit Diagram of Simple FM Radio Jammer

Note: This circuit diagram has been taken from website.

FM Jammer Circuit Explanation:


  • The variable capacitor C1 and L1 will constitute the tank circuit which will produce the high frequency signal, the capacitor C1 is variable so that we can produce different frequency signal by adjusting the variable capacitor. When the Q1 is turned ON, the tank circuit will start its operation and produce the VHF signal (very high frequency signal) which will jam or create the noise in the original signal so that receiver cannot receive the signal. Even if it is received also, the signal cannot be used by the receiver circuit.
  • The resistors R1 and R2 will act as the biasing circuit and R3 is used for limiting the emitter current in the circuit.


  • This type of circuit is banned in many countries. Use it by your own risk.
  • Capacitor C1 value should be changed for every station for getting the different frequency.
  • Different frequencies can be achieved by changing the values of capacitor and inductor. The formula is F= 1/ (2*pi*sqrt (L*C)).


Applications of Jammer Circuits:


Normally jammers are used in government offices in some countries, but jammers are mainly used by military, navy, air force and entire defense systems. People will not use jammers everywhere, but they use in selected places and highly confidential meetings, gathering etc.


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