Freeze Alarm (CB14454E)

The circuit of a 1968 publication can be implemented with more modern transistors such as BC548 for NPN and BC558 for PNP.

Current regulator (CB9158E)
This circuit was found in Radio Electronics from the 90s. The transistor is for general use. The...
48V Current Monitor (CB5243E)
We found this circuit in a 2005 Linear Technology application manual. The circuit makes use of a...
Precision Voltage Follower (CB13393E)
This circuit is from 1971 American documentation. Transistors are still common except for 2N2060...