Crystal Oscillator (Tester)¶
The circuit given below helps to test crystal resonators. Tested it and worked for testing crystal resonators of 8MHz, 12MHz, 16MHz and 20MHz.
However it did not work for crystals of 32.768KHz, we use in clock circuits. It also did not work for 48Mhz I had, but frequency might be high for my 100MHz oscilloscope to handle any way.
Initially on breadboard, used 2N4401 as transistors Q1 and Q2. Note sure if because of that, it did not work for 16MHz and 20Mhz crystals. Replacing them with 2N2222 cause it work for 16MHz, but still 20Mhz was not working. 20MHz started work after made circuit on a piece of perfboard.
I tried and verified working of this circuit.
PCB layout of though-hole components on a perfboard. Components are on top side of the board and green lines are tracks on back side of the board. That single brown line is jumper wire on top side of the board.
I built board with above layout.
- The circuit is taken from this YouTube video https://www.youtube.com/watch?v=blalAktxFoI.
- Found exact same circuit on this post too https://ac7lx.wordpress.com/2018/07/31/back-to-basics/.