This circuit applies to an old dial phone by detecting light pulses in the dial. The circuit is from an old 80's Electronic Design.
This circuit provides an output voltage when the input voltage is in the range between V1 and V2...
This circuit was found in a 1967 translation, but it can be easily assembled, as most components can be...
This low Power simple amplifier is intended to the use with high impedance phones. The circuit is...