Transistorized VU (CB21729E)

The instrument of this circuit can be a common microammeter. The circuit has its operating point adjusted in the trimpot.

Transistor Gain Meter (CB13271E)
This circuit is from an old documentation from the 70s, so the transistors used are not common....
Flip Flop Debouncer (CB4813E)
EDN magazine in a 90's issue published this TTL technology debouncer flip flop circuit, in this...
MOSFET Dip meter (CB9707E)
Found in old documentation, this circuit uses a double gate MOSFET. The operating frequencies...