High gain microammeter (CB22305E)

This circuit is from an American transistor book from the 60's. The transistor is germanium of the time.

Laser Diode Power Supply (CB15030E)
This source allows the supply of laser diodes with voltages above 11 V. The circuit is from French...
Frequency doubling oscillator (CB9634E)
This circuit uses an 18 MHz crystal to generate 36 MHz signals. We found it in an 80's...
Negative Line Current Monitor (CB5244E)
This circuit monitors the current in the negative line. The circuit is from a 2005 Linear...