Nov 06 2011

Transistor Driven Relay Switch Posted 193 days ago ago by Derek Backus     0 Comments

It seems every automation project we do here requires some type of low voltage, low current output to some type of higher voltage, higher current output. In our shop, this is usually the output of a Parallax Propeller chip to drive a relay. This allows us to switch just about any circuit we can dream up. Often we find ourselves turning to a very basic but essential circuit.

Parts List

D1     1N4002   
Q1     2N2222   
R1     390 ohm   
RLY1   Radio Shack 275-240   

As you can see, the parts list is short and... here's the best part... all of them can be found at your local RadioShack!

2N2222 Transistor with the Emitter, Base and Collector Labeled	390 ohm Resistor (Orange/White/Brown)
1N4002 Diode and Schematic	5V Relay

More Information

Parallax has a great article on how to implement this circuit and how to use a ULN2803 darlington array.

 

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