A Simple 4A Full Wave Bridge Rectifier
January, 2012full-wave bridge rectifier. It is useful for projects which will run off of typical household line voltages (e.g. 230V/115V-AC). It is a very simple PCB design that requires only 4 components; a diode bridge, 2 capacitors and a fuse.
The specs are largely dicated by the rectifier you choose. In this case I am using a Vishay GBL005 Glass Passivated Single-Phase Bridge Rectifier.
Absolute Maximum Ratings (TA = 25 ºC)
VRRM = 50V
VRMS = 35V
VDC = 50V
IF = 3A (PCB only), 4A with heatsink.
Typically I use them with a Radio Shack 12.6V CT 3.0A Chassis-Mount Transformer Part #273-1511. This transformer is able to convert 115VAC on it's primary to 12.6VRMS. With this transformer the two yellow leads are the secondary windings providing 12.6VRMS. I just cap off the black center tap wire. This gives me about 17.3 VDC on the rectifier's output.
Remember that the secondary voltage on the transformer is a nominal 12.6VRMS. I haveactually measured this to be about 14.8 VRMS which gives 20.9 VPP (VRMS x 1.414). A voltage drop of 2 diodes (VF = 1 V) yields 18.9 VPP, with some capcitor smoothing of the remaining 1.5V, pretty close to the 17.3 VDC measured.
Keep in mind that this is NOT a regulated DC output. It is only full-wave rectified, meaning it is not smooth. I use these where I might later replace it with a battery or other DC power source where the intent is to feed it into some sort of linear or switch-mode regulator.
You can put any size fuse you like (up to a max of 4A) in the holder, but I typically use a 3A fuse such as the Radio Shack 270-1009 3-amp 250V ACG Glass Fuse. If you plan on drawing more than 3A continuous you'll need to consider a suitable heatsink.
Here is an example power supply I built using the PCB bridge.