Practical crystal oscillator test circuit

The author uses a few simple components to create a test circuit that can measure 10kHz-100MHz crystal oscillator (the circuit is shown in the figure). BG1 and the connected resistor-capacitor components form a multi-frequency oscillator. After detection by C3, D1, and D2, the result can be obtained on the LED. Positive and negative voltages drive the LED to emit light. If the crystal oscillator is broken, the LED will not light up. This small circuit can be installed on the power supply for maintenance, leaving two small holes for inserting the crystal oscillator components. During production, please note that the two leads of the crystal oscillator cannot be too close to each other, otherwise the oscillation amplitude will be greatly reduced and the LED will not light up.