Re: Speaking of AC/DC

Posted by bobbapink on Feb 28, 2002 at 22:50

Re: Speaking of AC/DC (Bill Gill)

I expect it uses a solid state voltage converter, such as are used in computers and TVs. Nowadays they convert the AC voltage directly to DC, then use an electronic circuit to reduce it to the required voltage. For the amount of power needed to charge the battery(ies) in an electric razor they can probably get away with some pretty small components.

I gotta be quick here soÖ

Two things. Weíre talking about the conversion of AC to DC and the conversion of DC at some voltage to DC at some other voltage.

AC to DC is easily [and traditionally] accomplished using a full wave bridge rectifier. Basically four diodes cleverly connected and filtered with a capacitor (and possibly an inductor) to even it out to [ripple] DC.

Given DC to the desired DC is [usually] accomplished with a voltage regulator (most simplistically a zener diode and a load resistor) to obtain the desired voltage. These use to be found in discrete component but are most often now found in solid state chips or cans at five times the price (and 10 times the reliability, IMO)

Anyway, what we're talking here is the conversion of 110 VAC to about 4 VDC - all without the heat of a load resistor or the weight of a transformer. Something clever is going on.

I have not yet investigated but i shall do so tomorrow when the wife isnít watching (she hates it when I take things apart because historically thereís only a 50/50 chance Iíll get them back together).

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