0
\$\begingroup\$

I'm working on a project for school to monitor a 6 and 15 VAC signal coming in at 11KHz for both. I'm trying to find a simple way of recreating that at home for running some tests on circuits I'm developing. I have a simple function generator but it only goes up to 5VAC and has a very low current limiter so that's not an option and I'm poor so I can't afford a lab grade function generator.

Ideally, I just want to breadboard a few components that I can repurpose later if I need to. Reading up on some other posts I found Changing the frequency of an AC supply and the common suggested answer was "a rectifier followed by an inverter".

I found DC-AC Inverter Circuit - Toshiba Semiconductor (PDF) which explained a bit but it's still muddy for be. I understand I need to rectify wall supply 110VAC to a DC voltage then use an inverter to convert it back to an AC voltage. What I'm unclear on is how:

do I convert to 6 and 15 DC OR do I convert to a 12 and 30 DC (because the AC will do half positive, half negative)?

then use an inverter to make it AC at 11KHz? would it be PFM?

Any help or examples would be appreciated because most of the circuit examples I've found in my research are for converting 12VDC battery to 220VAC or 110VAC, AC to DC (guess I could just use it backward) but with no mention of frequency modification, or AC to AC but again no mention of frequency modification.

\$\endgroup\$
1
\$\begingroup\$

11kHz is well within the audio frequency range. So if you have access to an audio power amplifier, you could just feed your existing function generator into that. Otherwise, make an audio power amplifier out of common components.

\$\endgroup\$
0
\$\begingroup\$

First question: Your "simple function generator" was ruled out because it has a very low current limiter. So, what current do you need on the 11kHz signal? Or, to put it a different way, what's the input impedance of your circuit for the 11kHz signal? If your circuit has high input impedance, you can just use an op amp to bump the signal from your simple function generator up to the required voltage.

If your circuit has a low input impedance (i.e. draws a lot of current from the 11kHz signal), then yes, you'll need to build up an inverter. I won't go in to detail with that until you update the question to say how much current you're drawing.

\$\endgroup\$
0
\$\begingroup\$

As @selvek suggested and what I found it is hard to change the frequency but not too hard to change the voltage using an op amp. I had to make a lot of supplies for my setup so I ended up just going with putting in my function generator that unfortunately was capped around 6VAC (around 5-5.5 but close enough) and used a Non-inverting Operational Amplifier to step it up using the +/-15DC supplies I had to be the +/- references for it. Thank you for your input.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.