Bistable light relay (CB21708E)

This circuit was found in an internet documentation. The relay must have voltage according to the supply.

Sample and Hold LM3900 (CB14218E)
The circuit shown is suggested by National Semiconductor's Linear Applications Handbook. The base...
Telephone amplifier (CB8630E)
This circuit uses a pickup coil to take the signal from a telephone line without contacts. The circuit...
Opto and Strobe Interface (CB16037E)
In this circuit, the transistors are NPN for general use and the phototransistors can be replaced by...