Hello everyone,
I'm working on an RGB led strip controller, So I've got a 12v 6A "brick" (laptop like) power supply for it from ebay (
).
I tried measuring the voltage directly on the end of the connector (with a "springy" ground lead) - See the attached waveforms.
One set is with a 2A load (5 meter rgb led strip fed from only one side with all leds on) and the other set is without any load.
There seems to be noticeable ripple at 50Hz and 52KHz, which are the ac power line ripple and the PSU switching frequency (i'd assume).
My controller would have an MCU at 3.3v, and I plan to use the internal ADC on it to sample an electret microphone so I'm planning on using an opamp to amplify the mic, I wish to power the opamp from a single supply of as high voltage as I can (up to 12v).
Is the power supply too noisy for this ?
If so, How should I filter it ?
One more thing I noticed, the power supply has a 3 lead power connector, but when I took it apart I noticed the ground on the input connector isn't soldered nor connected anywhere.
When I probed the supply output voltage, I noticed tiny sparks when the scope's ground lead got really close/touched the power supply's ground. Is that normal ?
Thanks in advance,
Mike.