Relay driver (CB20549E)

Found a documentation on PCs from 1996, this circuit can be used as a shield. The relay is rated at 100 mA of coil current.

CMOS Oscillator (CB25040E)
This circuit is from Radio Electronics from February 1987. The frequency is given by the crystal that...
LASCR Controlled Oscillator (CB13888E)
In this circuit, a light-sensitive SCR or Light Activated SCR determines the operation of an...
Hearing Aid Amplifier (CB21798E)
This 3-transistor circuit was found in a Mullard manual from 1960. The transistors are germanium of the...