Hi everyone,
I'm currently working on a project for my university but we're being restricted in components. For the last section that I have yet to complete I need to make an oscillating circuit based off of a 75kHz tuning fork crystal.
I have some other components to use, A 74HCT04 NOT Gate (Buffered I think), an MCP602 (opamp) and TL82CP (opamp). Any caps and resistors are available as well.
The circuit must output a 5V peak to peak square wave with a 2.5V DC offset (so basically 0 to 5V square wave).
The Crystal I have, I measured to have a frequency of 74997Hz, ESR of 33775 Ohm, Cp = 1.5pF, Cs = 1fF and L = 4503H. The series capacitance value was recommended by my lecturer.
Does anyone have any recommendations for what I can try, as I've struggled to build anything let alone simulate it in LT SPICE.
PS: I've tried to use the NOT gate, but it's not working as I think it is buffered (from what I can understand from the Data Sheet). Our lecturer recommended putting an LP filter between 2 op-amps in an inverting and non-inverting config; the crystal is then connected between the other ends of the op-amps. The problem is I have no idea of how to get this to work
Regardless,
If anyone has any advice for me, as I can't find much on low frequency oscillators, please do let me know.
Thanks in advance!