Re: need a transformer

Hi Jesse,

I just noticed you wanted a 75 volt transformer.

that will be WAY too much.

the transfomer will take AC and turn it into AC. and you probably
have heard the term RMS. (Root Mean Square) basicallly, that RMS
means the 'average' voltage.

but, as you know, the AC wave has peaks and vallys.

the peaks top out at a higher voltage, but averaged with the valleys,
you get RMS.

for a DC power supply, you get the peaks without the valleys.

this is because the bridge rectifier converts everything to DC and
then the capacitor stores the charge. the capacitor 'fills' at the
voltage of the peaks.

so, the proper formula is AC voltage from the transformer, less the
voltage drop of the bridge rectifier, then that voltage times 1.414 to
get the DC voltage.

so, your 75 volt transformer, less about 1 volt for the bridge = 74
volts. 74 volts times 1.414 = 104 volts !

working backwards, 75 volts DC divided by 1.414 = 52 volts. so you
probabluy want something around 48 to 54 volts to get 70 to 75 volts
DC on the DC side.

Check E-Bay for TOROID and look over the units. they should have
something that meets your needs.

Dave