When wiring a bridge rectifier where does the black and white wire go from the AC source and where does the DC - get connected to assuming no capacitor is used but the DC - just goes to a cell?

Answer 1

If your bridge rectifier doesn't have the symbols on the package to tell you how to hook it up, you will have to identify the bridge connections to hook it up properly. Let's look at a case with four discrete diodes and explain that. Then you should be able to take that to the full wave bridge and hook it up. Four similar diodes properly rated are going to be used in a bridge rectifier. The diodes have symbols on them, and the symbol is an arrow pointing to a flat line. The flat line is the n end of the p-n junction of that diode. Another way to say this is that the arrow points to the n-type material. The end behind the arrow is the p end of the p-n junction. On a diode, the "band" around the component is the end the arrow points to, or the n end of the diode - the n-type material end of the device. Connect the n ends of two diodes together. That means two diodes will have their arrows pointing at each other. That point of the bridge is the positive (+) side of the bridge. Now take a diode and connect it to one of the open leads of the two diodes connected together. Make sure the diode you are adding points toward the one to which your are connecting it. That means that the arrow will point to the back of the arrow of one of the two connected diodes. Do the same with the last diode and connect it to the other of the two originally connected diodes. Now connect together the open ends of the last two diodes you connected. That last connection will be the negative (-) end of the bridge rectifier. Connect the AC to the other "corners" of the bridge. It doesn't matter which wire goes where. It's AC, and the polarity of the applied voltage will be alternating. Use the provided link to the Wikipedia article on the diode bridge to see how it is connected and how it works. Note: Work safely at all times and never energize something you are uncertain about.
A true bridge rectifier has 4 connections, two are for AC input and two are for DC output.

It doesn't matter which way you connect the two AC inputs, so long as they are within the voltage specifications of the bridge. The output will be as labeled on the bridge with + voltage coming out the + connection and - voltage out the - connection.

You also need to make certain that the current load does not exceed the capacity of the bridge.

On the other hand, if you're trying to build a bridge rectifier from diodes, send me an e-mail address and I'll send a drawing. My e-mail address is on my bio page.