The following circuit of special functions to detect the presence or absence of signal AF / RF. This circuit is very simple so as to make it requires a relatively low cost. Detektor Signal AF/RF circuit based an audio amplifier and a loudspeaker with a switch input to the AF and RF signal. The whole device can be made as small as possible so that it can be included in a container to keep the peace.
Audio amplifier section in this series created by IC TDA 2822M, with a low-power stereo amplifier in 8-pin mini-DIP. This IC is used as a bridge cofiguration to minimize output power up to 250 mW, the loudspeaker is in use 4 ohm, 500mW. Current required is less than 10mA with a 3V battery voltage.
Audio amplifier section in this series created by IC TDA 2822M, with a low-power stereo amplifier in 8-pin mini-DIP. This IC is used as a bridge cofiguration to minimize output power up to 250 mW, the loudspeaker is in use 4 ohm, 500mW. Current required is less than 10mA with a 3V battery voltage.
Skema Rangkaian Detektor Signal AF/RF
List Component
R1 : 22K
R2, 3, 4 : 4K7
C1 : 1n
C2, 6, 7 : 0,1uF
C3, 4 : 10uF/16V
C5 : 0,01uf
D1 : OA79
VR1 : 22K
IC 1 : TDA2822M
LS : 8 ohm 500mW
When the switch in the AF position, Signal input audio input working on AF amplifier (IC 1 pin 7) via a capacitor C2 and Potentiometer VR1. Capacitor C2 is always holding the input amplifier of the DC voltage and make it happen in the audio signal frequency. Input signal IC 1 can be arranged with the help of potentiometer VR1.
When switch on the RF position, the detector and demodulator circuit formed by capacitor C1, diode D1, and resistors R1 and R2 are connected to the input rangakaian. When the audio signal is detected it will be significantly strengthened in kerangkaian for. Signal detection is done by plugging in tactile (probe) on the legs of the existing components.
