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

Tiny 1MHz Lowpass Filter Uses No Inductors
Video amplifier provides digital gain control
VFC110: Single Chip High-Frequency Voltage-to-Frequency Converter (VFC)
the active power factor correction (PFC) of FAN4810 Circuit design
Switching Power Supply
hi fi stereo multiplexer for fm
pills reminder schematics
Water Meter Monitor
fm radio receiver
Battery Replacement Power Supply
telephone ring generator circuit
Automatic lighting control circuit diagram composed of optocouplers