The circuit presented was found in the Linear Applications Handbook of the National Semiconductor of 1994. It is based on a DAC1020 and operational not common today.
The circuit shown is suggested by National Semiconductor's Linear Applications Handbook. The base...
This circuit uses a pickup coil to take the signal from a telephone line without contacts. The circuit...
In this circuit, the transistors are NPN for general use and the phototransistors can be replaced by...