I'm way out of my comfort zone here. By "It" above, you mean the PZT? If so, my only answer is 'maybe'.wait a minute 20 kom at 1MHz is only 5 pf
how can it only be 5 mA?
It must be really tiny.
But in another part of the paper they have this diagram where the PZT element(s) are embedded into the side wall of a hyperdermic needle:
View attachment 133834
If that needle is large enough to embed a 3.2mm diameter PZT in its sidewall; I'd drop-kick any doctor that approached me with it in his hands. Geez!.
Thank you for that.Attached is a pseudo schematic
Thank you for that.
One (of possibly many) questions. Any particular reason for using a microcontroller to generate the square wave rather than VCO (say SN74LS624)?
If the project goes anywhere, it will need a microcontroller, but doing anything else on a µCPU whilst maintaining a high frequency loop gets messy.
/I had a dyslexic moment'scuse my ignorance of these things, but typing 74ALC into mouser finds nothing, and I have no idea what I am looking for. Hints?
I also did a sim of of your circuit above and wrote a short script to calculate a range of RC values from an input frequency 100kHz, 1MHz, 10MHz, (trying to cover all bases) they produce voltages close enough to 100V for those frequencies. Update: And it just dawned on me I got 200V p-p!)If you don't understand Q resonance, I can link to an RLC nomograph. or PZT impedance, look up crystal impedance.
Computing / building the piezo PZT RLC values is essential before doing anything.
even the contact with skin will add pF and so the design will keep changing .... that is until you establish the design specs. !!