Can I use DC to run an AC device in some cases? [closed]

Question

I think there may be devices specified to use alternating current (AC) which can run supplied with direct current (DC) instead.

There are devices which depend on AC in some fundamental way, like a motor creating alternating magnet fields. These do not work on DC.

But other devices use DC internally, but are specified to run on AC. They convert the supply current to DC as the first step.

I would like to run a device that is specified to require alternating current using DC, because DC is easily available. The device seems to use a full bridge rectifier (consisting of four diodes) as the first step of using the supplied power.

I think for a device like this, DC should work. But if so, it is not clear to me which voltage to use, in relation to the specified AC voltage.

Do you think the case above would work? How to decide for which devices it works?

Answer 1

Any device that has a rectifier at the input and has no direct use of AC is a good candidate for operation by DC input. You need to determine the DC operating voltage and make sure that the capacitor charging current is not excessive. Some kind of recharge circuit may be required.

If the rectifier output has a capacitive filter, the DC voltage will be close to the peak of the input voltage waveform, RMS voltage multiplied by the square root of 2. You need to determine if mains voltage is rectified or if there is a transformer feeding the rectifier.