AF/RF signal detector

The circuit that we will make this a special electronic circuit which can be used to detect the presence or absence of signal AF / RF. The circuit is very neat and simple to make. 

The cost involved was too low. If the reader has to assemble this circuit, it is easily the reader determine whether there is AF or RF signal to a particular part of a circuit. Basic circuit uses an audio amplifier and a loudspeaker to the input switch to AF and RF signal. The entire device can be made as small as possible so it can be put in place to maintain security. Audio amplifier section in this series created by IC TDA 2822M, with a low power stereo amplifier in 8-pin mini-DIP. IC is used as a bridge cofiguration to shrink up to 250 mW output power, 4 ohm loudspeaker used, 500mW. 

Current required is less than 10mA with a voltage of 3V battery. The series of work When the selector switch to the AF position, working on the input audio signal AF amplifier input (pin 7 IC 1) through capacitor C2 and the potentiometer VR1. The capacitor C2 is always withstand voltage of the DC amplifier input and make it happen in the audio frequency signal. IC 1 input signal can be adjusted with the help of potentiometer VR1. When the selector switch on the RF position, the detector and demodulator circuit formed by capacitor C1, diode D1 and resistor R1 and R2 are connected to the input The set. When the audio signal is detected then it will obviously get the circuit to be strengthened. Signal detection is done by plugging the feeler (Probe) on the legs of the existing components.