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.
This circuit provides a pulse train of 4 MHz or at another frequency determined by the crystal during...
The number of pulses produced by this circuit depends on the switch pressed. The circuit is from...
This circuit prevents the passage of frequencies in a range starting at 1 kHz and can be adjusted...