Switch 6v transistor with an Arduino

Hey,

So I've bought some DIN Relays (see note 1 and 2) but they require 12v to switch. My goal was to switch the relay with an Arduino so I've bought an external 12v power supply and some transistors (c557b). The only problem is that I've bought the wrong transistors because they require 6v to switch so I can't switch the transistors as there's 5v on the IO pins. I'm wondering if there's a solution to switch the current relay and transistor without buying new transistors.

Parts I currently have which I can use:

  • c557b transistor
  • 470K, 220omh and some other resistors
  • capacitors
  • BT136/500 triac
  • opAmp IC
  • MOC3021 optocoupler
  • arduino's
  • And some other parts

Thank you,

Pascal

Note 1: https://www.vekto.nl/nl/relais-1xwissel-12a-24vdc.html
Note 2: https://www.vekto.nl/nl/dinrail-voet-1xwissel.html

https://www.digikey.com/product-detail/en/fairchild-on-semiconductor/BC557BTA/BC557BTACT-ND/3042484
That transistor can be driven from an Arduino pin. Use a 470 resistor between the Arduino and the base, that will put
(5V - 0.65V)/470 ohm = 9.2mA into the base and putting the part into saturation, letting the relay coil current flow.
It's only rated for 100mA max, hopefully your coils need less than that. I can't open those links from here. (network issue).

Sorry, I didn't realize that c577b was a PNP, not an NPN.

You need an NPN to either sink current from the PNP base to turn it on, or to sink the relay coil current directly: