Variable regulator with crowbar protection (CB21189E)

This circuit was found in a Popular Electronics from the 90's. The power transistors must be equipped with a heat sink.

Nonlinear Gain Amplifier (CB6130E)
This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used...
Heads or tails (CB22061E)
This circuit uses an operational amplifier that is still common today. The indication is made by...
Micro Power Comparator (CB14174E)
The circuit shown is from the National Semiconductor's Linear Applications Handbook. The CI is not...