PLL (CB7971E)

This common operational PLL circuit was found in a Popular Electronics 90’s. The power supply need not be symmetrical.

Positive Comparator (CB24963E)
The circuit with a common operational amplifier uses a zener as a reference. The circuit is from...
FM modulator with 555 (CB12102E)
In this circuit we show how to modulate the pulses produced by a 555 in frequency. The circuit can be...
2 LED flasher LM3909 (CB20945E)
This circuit was found in a Popular Electronics from the 80's. The circuit can be powered with...