Telephone handset tone dial encoder

Posted on Jan 1, 2013

This encoder uses a single contact per key keyboard and provides all other switching function electronically. The diode between terminals 8 and 15 prevents the output going more than 1 volt negative with respect to the negative supply V-

Telephone handset tone dial encoder
Click here to download the full size of the above Circuit.

The circuit operates over the supply voltage range from 3 volts to 15 volts.

Leave Comment

characters left:

New Circuits



Popular Circuits

220 Volt Disco Lamp circuit
Crystal Set 1
Trf3703 Quadrature Modulator Evaluation Module
fm transmitter colpitt oscillator
Improved 3 Transistor Audio Amp (80 milliwatt) circuit
Arduino Vocal Effects Box
Motor vehicle steering flasher 12
STK6327A application circuit
555 as the core of a circuit diagram of proximity switch