Current indicator (CB22132E)

In this circuit the voltage across the LED is limited by the diodes. The maximum current also depends on the resistor.

30 and 50 V power supply (CB8678E)
This source was originally suggested by Delco in a 1969 documentation to power amplifiers up to 50 W. The...
Intercom for noisy environments (CB21069E)
Found in a Popular Electronics from the 90s, this circuit is suitable for communication between rider...
Analog switch (CB21264E)
Found in an Analog Devices documentation from the 1990s, this circuit uses components that admit...