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 transmitter was sent by contributing reader Adriano Muniz Moura from Pirapora – MG. It is in...
This circuit indicates whether the voltage to be measured is higher or lower than the zener diode...
An interesting application that can be implemented with the LM139 is the pulse width modulator. This is...