This circuit is one of many that the reader can find in this section for testing crystals. The circuit uses an indicator LED. Transistor Q1 determines the maximum crystal frequency that can be tested.
The indicated circuit performs a slow charge of 12 V batteries maintaining a constant current of...
Found in a 73 magazine from the 1980s, this circuit generates signals from 3.2 to 22 MHz. FETs can be...
In the figure we have a three-phase AC motor control for voltages up to 600 V or 1200 V depending on...