MiniPulse Pluse audio options

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I will run your simulation and give it a try as you have explained, I always see such graphs (Freq. vs Voltage plots) with respect to VCO circuits. Nice to know how to actually execute such a task in LTspice.

Thanks Qiaozhi.

[Polymer]

Now that I am in quarantine, I have been feeling motivated once again to re-engage in hobby building and tinkering.
Only one big problem..... I AM RUNNING OUT OF SOLDER!!!!

All local non-essential businesses are shut down. Supermarket does not sell solder.
Rrrrrr.....

Same here, I'm running out of solder too. My last buy of rolls abroad was round 5 years ago.
In the meantime getting leaded solder is very difficult in the EU as I have found out, only if you have a justified business for that.

I call RoHs faux environmental reasoning.

I really like the Kester 44 (63/37 or 60/40), which oddly enough is not so common in the EU.

A lot of other name brands here have fluxes which I am not fond of.

Good luck with finding good solder or getting it shipped to the island!

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What would be the preferred way to connect an audio chopper to a PI output, a JFET or an ordinary bipolar transistor?

I'm going to try the VCO circuit in the above posts.

I plan to take the input from after the sampling integrator and connect the output via a JFET transistor after the second integrator. I will condemn the 555 VCO section and just add an audio amplifier stage to drive a speaker or headphones.

I'm not sure about the voltages though.

Any help or advice please.

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Would a simple 4046 work for you

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I found this modified vco, works inversely
http://www.next.gr/oscillators/volta...co-l13874.html

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I came across this VCO circuit with an ltpsice simulation to play with.

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This one looks interesting, I think I've seen this circuit adapted for a surf PI project. Would be interesting to see what the frequency vs voltage plot looks like.

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" A 555 VCO circuit with logarithmic characteristics"