The circuit shown is from Motorola's 1990 Linear Databook. Shaded components are optional. The characteristics of the coils are given next to the diagram.
This circuit can generate signals in the range from 1 to 20 kHz, depending on the crystal. The...
The basis of this circuit is an LM380 that drives a speaker that emits sound when moisture is...
Using the ICM7555, CMOS version of the 555, this circuit produces a 1 kHz signal. The circuit has...