DTMF stands for dual tone-multi frequency signal which is applied as the basis of telephone system and functions as a device that produces tones as the phone button is pressed. DTMF signal is also applied in remote control circuitry for frequency modulation of the carrier. The DTMF signal is connected to a DTMF to BCD converter whose BCD output is used to switch on and switch off various electrical appliances. In order to generate DTMF frequencies it requires IC UM91214B with 3V energy consumption which is provided by simple zener diode regulator that is able to convert 9V into 3 V to be used by the IC. Here is the circuit diagram of DTMF dual tone multi frequency on remote control application which consists of VC 1 0-22pf trimmer, IC UM91214B, D1 3.3V zener, IC 2 KT3170/8870, IC4CD4013, 6V relay, etc.
DTMF Dual Tone Multi Frequency on Remote Control Application Circuit Diagram
July 19, 2011 by Leave a Comment