I want to build a low frequency (around 10 Hz) and low voltage (about 3V) sine wave generator to drive an electro magnet. It would be very helpful, if you can suggest few efficient ways of doing this.
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1\$\begingroup\$ DDS comes to mind. \$\endgroup\$– Ignacio Vazquez-AbramsApr 30, 2015 at 1:35
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1\$\begingroup\$ What voltage supplies are available? 3.3v? 5v? +/-5v? +/-12v? And how much current do you need to provide? \$\endgroup\$– WhatRoughBeastApr 30, 2015 at 2:11
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\$\begingroup\$ How much distortion is allowable? \$\endgroup\$– Dwayne ReidApr 30, 2015 at 2:12
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2 Answers
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To generate the sine wave, there are a few possibilities- AD9850 DDS modules are readily available, as are other DDS in chip form (you'll need a micro to set them up).
A micro could be used directly, using DAC or PWM output. You would implement a sine lookup table.
A triangle wave oscillator is easy to make with a couple op-amps, the waveform can be flattened with diodes and resistors or JFETs (I don't recommend this old school method -too many parts- unless you have a real aversion to digital).
To actually drive the electromagnet, you probably need a power amplifier, and the details will depend on the current required. It could be just an op-amp, a high current op-amp, or perhaps something more substantial would be required. You might need +/-6V supplies (plus a low voltage digital supply) to generate a 3V RMS sine wave.
answered Apr 30, 2015 at 9:03
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I'd suggest free audio function generator software running on a PC or smartphone, then take the sound output to an audio power amp that has good bass response. The output of the audio power amp should give you what you want, and it's now really easy to play around with the frequency, amplitude, etc.
Good luck!
