Fahrenheit Sensor LM34 (CB14400E)

This circuit measures temperatures from +5 to + 300º F using a sensor from National Semiconductor not very easy to obtain.

Reference Voltage Amplifier (CB4906E)
This circuit is from an old manual of operational amplifiers. The setting can be adapted to work...
Logarithmic Amplifier (CB13213E)
The operational amplifiers used on this Motorola circuit from the 1970s are no longer common, but...
Shadow locked relay (CB21999E)
This circuit uses a feedback system that latches the relay when closed. The circuit uses an...