noise: re Dynamo Regulator Help
johnyradio at gmail.com
Mon Jul 22 00:44:04 UTC 2013
Henner Zeller h.zeller at acm.org
Sun Jul 21 22:07:55 UTC 2013 wrote
>>If it is a DC motor, it will output DC with a bit of noise.
--it clearly outputs an oscillation. Isn't an oscillation always AC,
even if it's offset above zero, and never goes negative?
>>60000 RPM, which is way higher than what typical small motors usually
--it takes 30+ volts on the power supply of the OTHER DC motor (which is
used to spin the shaft on the "oscillator" motor)
>>Before connecting to the amplifier, use the multimeter to measure
that the AC voltage is in the order of 1V, which is a typical input.
--cool, will try
>>It is the voltage or the DC part of the voltage that is killing your amp.
--i did try a 100uf series cap on one of the terminals. Did not protect
>>If you voltage is _way_ to high (which I suspect is happening here),
then you can blow the input stage, because you send too much current through
--um, current? or voltage?
>> the resistor you have 'on the outside' forms a voltage divider with
the input impedance. If they are in about the same order of magnitude,
you get half the input voltage.
--then shouldn't the series resistors i used give me significant
overdrive protection? They seemed to have no affect.
>>It does sound you operated the motor way out of its specs.
--in what way?
>>a DC motor does _not_ generate a sine wave, at best it returns a wave
that you would get as the result of rectifying a sine wave; that is what
the commutator is for. If it is an AC motor, then you get a sine wave.
--on the scope, it sure looks sine-like. But also weird.
Stick It In Your Ear!
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