I'm trying to build a circuit to switch a 5v relay that will operate an appliance plugged into the wall, but am having trouble understanding the schematic shown in the playground: http://www.arduino.cc/playground/uploads/Learning/relays.pdf
I am using Relay http://us.100y.com.tw/pdf_file/LU-SERIES.pdf
(LU-5), transistor BC 548B http://www.philohome.com/sensors/gp2d12/gp2d12-datasheets/bc548.pdf, and have tried a 1k and 2k2 resistor, on the diode it says '1N4004 938'. I'm brand new to electronics so am sure it's something simple that I've missed, but have been trying to make it work for a couple of days now unsuccessfully. It's doing my box in!
I am trying to run the circuit from the blink example (to check i've got the circuit right before worrying about the code), but nothing happens. I've tried various wiring configurations. The relay works fine when all other components are removed, and attached to pin13/gnd or 5v/gnd.
I tried to attach a photo, but just got 'img', so here is my circuit at the moment:
FROM TRANSISTOR: EMITTER TO GROUND, COLLECTOR-DIODE-RELAY-GROUND
Both transistor and relay are grounded to the GND pin next to 5V on the Arduino.