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.

Crystal switched oscillator (CB9632E)
This oscillator with crystal for overtone operation was found in an old American documentation. The coil...
Basic PLL (CB21757E)
In the figure we have a basic PLL circuit with the LM567 or equivalent. The circuit is from a 1977...
DC and Stepper Motor Controls with the A3906 (CB23592E)
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single...