When two semiconductor diodes are packed in a single body than they are known as double diodes. These are of two types :-
- Common cathodes double diodes
- Common anode double diodes.
Common Cathode Double Diode
In these types of diodes, cathodes of two diodes are connected together and two wires are taken out from the two anodes.
Common Anode Double Diodes
In these types of diodes, anodes of two diodes are connected together to make common anode and two wires are taken out from the two cathodes.
Construction of a bridge rectifier with two double diodes
InBridge rectifier there are four semiconductor diodes and four electrodes are taken out from them. These are used as shown in the figure. Pirn iro OA Four semiconductor diodes can he connected externally to make a bridge rectifier
In order to check the four diodes of bridge rectifier, check two ends like a single diode. According to the fig. no, I & no.2 is a diode, no.2 and no.3 is another diode, no.3 &no.4 is third and no.4 & no.I is fourth diode. Each diode is checked with the multimeter is order to check a bridge rectifier.
Testing diode through multimeter sanwa P-3:
We can give forward biasing or reverse biasing to any diode through multimeter sanwa P-3. We know that diode only conducts during forward biasing. It does not conducts during reverse biasing. If it conducts during reverse biasing than it is short, but if it does not conducts during forward bias than it is open. While checking semiconductor diode* with a multimeter than both the bias is forward and reverse bias must be given to it. Double diode can also be checked with a multimeter just like a semiconductor.