davelectronic
- Dec 13, 2010
- 1,087
- Joined
- Dec 13, 2010
- Messages
- 1,087
Ive been meaning to build a big linear power supply for a while but not got there yet, anyway i think i know the answer to this question, but want to run it past the more experienced here.
I have a good source of toroidal transformers of varying secondary voltages 12 / 18 / 22 / 35 volts RMS AC, i am after a target voltage of 13.80 volts DC.
My problem is most of the suitable units are 12 volts AC, so after smoothing and rectification i would get about 16 volts DC, but as this is border line for linear voltage regulators is it to low, i know a transformer of 15 volts RMS secondary is fine as it allows that good margin of a few volts over for the rectifier and regulator.
So would a 12 volts RMS secondary after rectifying and filtering allow an output of 13.80 volts DC under load conditions, i don't think it will as there would be not enough over head to allow the regulator to function properly, only wanted the voltage low for maximum current, and the supplier has a good stock of 12 volts units.
The higher voltage units would create to much heat in the regulator i think, any thoughts appreciated.
I have a good source of toroidal transformers of varying secondary voltages 12 / 18 / 22 / 35 volts RMS AC, i am after a target voltage of 13.80 volts DC.
My problem is most of the suitable units are 12 volts AC, so after smoothing and rectification i would get about 16 volts DC, but as this is border line for linear voltage regulators is it to low, i know a transformer of 15 volts RMS secondary is fine as it allows that good margin of a few volts over for the rectifier and regulator.
So would a 12 volts RMS secondary after rectifying and filtering allow an output of 13.80 volts DC under load conditions, i don't think it will as there would be not enough over head to allow the regulator to function properly, only wanted the voltage low for maximum current, and the supplier has a good stock of 12 volts units.
The higher voltage units would create to much heat in the regulator i think, any thoughts appreciated.