How to amplify a square wave cheaply at 100 Hz?

[Guest plukens]

I am driving a piezo disk at 100 Hz (or less) with square wave and am limited by the output of my signal generator to 10 V.  I wish to amplify that to 50 or even 100 V.  How to do that cheaply?

Will an audio amplifier work?  They are designed to  drive low impedence loads (8 ohm for instance).  How will that work with a high impedence load (my piezo disk)?

My budget is $50, ok $100 max.

Thanks!

Peter

[Kevin Weddle]

A voltage multiplier might be a consideration. A very simple peak detector in series with a resistor and capacitor load on the piezo could supply adequate squarewave voltage. The parallel RC will be designed for the frequency of 100Hz or lower.

[Hero999]

Kevin,
A voltage multiplier converts AC to DC so isn't an option and the rest of your post doesn't make any sense.

plukins,
An audio amplifier may oscillate, as it won't be designed to drive a capacitive load.


Are you looking to build this yourself or buy off the shelf?

[Kevin Weddle]

A voltage multiplier developes a DC voltage from the positive or negative cycle. The input is capacitvely coupled and the sinewave has this DC offset. A squarewave cannot be coupled with a capacitor, so the output is this DC offset when not in transition.

[Hero999]

A voltage multiplier developes a DC voltage from the positive or negative cycle. The input is capacitvely coupled and the sinewave has this DC offset. A squarewave cannot be coupled with a capacitor, so the output is this DC offset when not in transition.

The piezo needs to be driven by a 100Hz square wave.

How can a voltage multiplier circuit (which will convert this to DC) possibly work?

If the signal generator had enough current capability (it doesn't) a simple step-up transformer would work but that's not an option here. An amplifier is required, which means a separate 100V supply voltage.