Looking for a power supply that can be modulated
Looking for a power supply that can be modulated
(OP)
Hi,
I am looking for a power supply that can be modulated from 50 Hz to 20 kHz with a peak-to-peak voltage of 4 V. The supply must be capable of providing at least 1 A and have an internal resistance from 50 m? to 150 m?.
I have never worked with a power supply that could be modulated like this before and am mostly interested in where I should start looking for one. Specific brand names would be helpful. Are there certain terms that describe supplies such as these (modulate-able didn't get me far)?
Regards,
David
I am looking for a power supply that can be modulated from 50 Hz to 20 kHz with a peak-to-peak voltage of 4 V. The supply must be capable of providing at least 1 A and have an internal resistance from 50 m? to 150 m?.
I have never worked with a power supply that could be modulated like this before and am mostly interested in where I should start looking for one. Specific brand names would be helpful. Are there certain terms that describe supplies such as these (modulate-able didn't get me far)?
Regards,
David





RE: Looking for a power supply that can be modulated
RE: Looking for a power supply that can be modulated
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RE: Looking for a power supply that can be modulated
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If we learn from our mistakes I'm getting a great education!
RE: Looking for a power supply that can be modulated
eBay probably has them now and then.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Looking for a power supply that can be modulated
The application is automotive testing (AC signal superimposed on DC to simulate battery and alternator).
I have a few Kepcos, TCRs, and Xantrex supplies- I was hesitant to use them since there isn't a specification for output frequency. I'll try them out and see what kind of results I get.
Thanks,
David
RE: Looking for a power supply that can be modulated
But for PSRR (?) testing as you describe, I seem to recall that it is very common to use just a normal power supply, but fed through (in series) the secondary of an audio transformer where the primary of the audio transformer is fed with the required audio signal. The net result is that the DC supply has imposed upon it the audio modulation. You might have to tweak the voltage a bit for the DC resistance.
In Military testing, the specifications and standards typically include a detailed 'how to' for each test. Doesn't the automotive industry provide a similar degree of guidance in their specs and standards? If not, then perhaps you should look up the closest applicable military standard and see their recommended (or mandated) test set-up.
RE: Looking for a power supply that can be modulated
My suggestion was going to to use a signal transformer, or at least one good up to the frequency of interest, and then drive the primary with a function generator via a transistor. You would need to tweak the circuit paramaters, but you should be able to use the transistor / transformer as a power amplifier to get the amperage up without excesively loading the function generator.
RE: Looking for a power supply that can be modulated
RE: Looking for a power supply that can be modulated
In place of VE1BLL's fine suggestion, I would subsitute a good quality audio transformer rather than a signal transformer. The power requirements suggested might lean to the former.
They should be relatively inexpensive and the 50Hz to 20KHz are well within the audio range for "high end" components.
Cheers,
Rich S.
RE: Looking for a power supply that can be modulated
RE: Looking for a power supply that can be modulated
Try it on one of your old linear psu's if you've kept any.
I would not reccomend using an audio amp unless it is rated for full power continuously, you will probably destroy the output stage.
RE: Looking for a power supply that can be modulated
RE: Looking for a power supply that can be modulated
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Looking for a power supply that can be modulated
They may still be able to be run in the mode the earlier DC300A amp could be used..
The Crown DC300A was called a "Laboratory Amplifier" as it could be used as a DC to 20khz DC servo amplifier.. There were DC balance controls behind the front panel that could be adjusted for high precision "critical applications" (their words)..
A little info on the DC300A.. http://www
Their amps have a reputation for being bullet proof. still have one running strong that I bought in the early '80s..
http://home.4x4wire.com/deddleman/
RE: Looking for a power supply that can be modulated
I Once disconnected the power amplifer from a small vibration table, and used it (carefully).
Another time, I had access to a wideband power amplifer from Krohn-Hite Corporation. http://www.krohn-hite.com
At one time, I planned on building a test fixture for a similar application using Apex precision power OP-Amps http://apex.cirrus.com/en/products/apex/index.html