MikkoP

Do you might know what these mean? Two of the transistors say BC547 and on the next line there is 943 and B on top of one of the legs. One of them says BC547 and on the next line 410 and the same B

Do you have something in mind?

They come from the controller. Blue is ground, black and green are 4,5 V. Connecting green and blue the car goes forward, black and blue makes it go backward

Hope these are clear enough mikko.peltoset.fi/circuit%20(1).jpg mikko.peltoset.fi/circuit%20(2).jpg

Sure, just a moment

Sorry for that, no minus in there, my bad

Around -2,8 V

Wait

Says -5 V

.. or base leg

Arduino is gettin power from different source than the radio controller because the controller wants 9 V. The grounds are connected to each other. I made sure the voltage is zero on the base by using a multimeter to measure it. I connected ground to ground and the voltage wire from the multimeter in the base pin

It's BC547

The isolation is fine. At the moment I just use digitalWrite to set the pin 8 low on Arduino.

Hi Rick. I have a radio controller stolen from my RC car's controller. To move forward I need to connect 4,5 V wire to ground. I've connected the 4,5 V wire to NPN collector and the emitter to ground. Now when I connect Arduino to the base the current starts flowing even I don't apply any current there

Hi there! Anyone here who knows Arduino or especially NPN transistors?