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Jon_G4MDC · 28th Aug 2019, 11:23 am

I have just entered that circuit in LT Spice with a 2N2222 as the active device and 10V as the power supply.

I used a guesswork crystal equivalent circuit which resonates at 4MHz and has an ESR of 120 Ohms.

It takes about 5mS to start and build to full output (high impedance load assumed) after which there is 0.5V pk-pk across the resistor representing crystal ESR.
That is around 0.26mW of dissipation and it should be safe against the rated 1mW for the crystal.

The 39pF capacitor will probably need adjustment to pull to exact frequency.

28th Aug 2019, 11:23 am	#10
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Crystal oscillator circuit design I have just entered that circuit in LT Spice with a 2N2222 as the active device and 10V as the power supply. I used a guesswork crystal equivalent circuit which resonates at 4MHz and has an ESR of 120 Ohms. It takes about 5mS to start and build to full output (high impedance load assumed) after which there is 0.5V pk-pk across the resistor representing crystal ESR. That is around 0.26mW of dissipation and it should be safe against the rated 1mW for the crystal. The 39pF capacitor will probably need adjustment to pull to exact frequency. Last edited by Jon_G4MDC; 28th Aug 2019 at 11:46 am.