Undervoltage detector with the LM3900 (CB25172E)

The figure shows how to implement an undervoltage detector using a Norton amplifier and a zener diode as the main elements.

Monostable LM3900 (CB15618E)
We can obtain a monostable circuit with two amplifiers, from the configuration shown in the...
Short wave converter (CB9185E)
Found in Radio Electronics from the 90s, this circuit converts signals from the 9.5 to 9.8 MHz...
741 Power Amplifier (CB26273E)
Found in a 1990s Popular Electronics, this circuit uses two transistors to boost the power of a...