Hi,

I'm planning on putting together something that converts line 120v AC to 120v DC @ 5A or so. What parts would I need in addition to a bridge recitifier and a heat sink?

 

You must plan on using a transformer. A secondary voltage of 80 - 90 volts will put you in the "or so" range - rectified and filtered DC is about 1.4 times the RMS voltage rating.

What's the heat sink for?

 

After the bridge rectifier use a capacitor filter ans then a buck DC-DC converter to regulate the voltage to 120V DC. A transformer is not really required unless you want isolation from the mains or to obtain a better efficiency of the converter.

 

Hello,

I think the use of a transformer is a must.
Either in a normal way like beenthere said or in a SMPS powersupply.
A transformer will provide a certain safety for you and others.

Greetings,
Bertus

 

Can the circuit be isolated without the use of a transformer? What if a circuit breaker is used before the power is connected to the main?

 

That does not provide any isolation. If a circuit is fed directly from the line, it is all too possible for someone touching any part of that circuit to become a current path from the line to ground, resulting in a fatal shock.

For that matter, working with a properly isolated DC voltage as high as 120 volts also presents a lethal shock hazard. We would discourage working with such voltages until you have a level of experience working with circuits that lets you know how to manage things safely. Any accidental contact with a live terminal can be deadly.

What are you trying to do?