Common collector stage (CB22227E)

Found in a publication from the 50's, this circuit uses a germanium transistor of the time. The power supply is simple.

Timer 555 (CB8111E)
Found in a PE Hobbyst Handbook of 1991, this circuit was originally proposed to time photographic...
Operational Amplifier NAND Gate (CB19395E)
This is the traditional configuration of an AND gate using an operational amplifier. Operational...
Telephone Call Sign (CB16888E)
The presented circuit activates a relay when a telephone call occurs. The relay can be used to...