So the three branches take 3*33=100mA from the battery. A red LED typically drops around 1.7 to 2.0 volts which makes 33mA per LED (which is a bit higher than the usual 20mA for LED). There is no detail about the LED type, assuming this is a red LED. There are three parallel branches, each consuming prox 33mA. There 's a quick schematic and photo to illustrate:įor the LED side, the total current could be reduced. I have put a 10 Ohms resistor between the GPIO and the Transistor Base to reduce a bit the voltage but is it really necessary? connect the base of this BC635 npn transistor to the Raspberry Pi GPIO (using #18)Ĭonnect the emitter to the Raspberry pi ground pinĬonnect the collector to the ground as wellĬonnect both 9V battery and Raspberry Pi ground breadboard linesĬonnect the breadboard '+' part with the 3 parallel LEDs (and resistors) to the 9V +Īccording to the BC635 Data sheet data sheet the max emitter-Base Voltage is 5V, and the Collector Current max is 1A (although on the Motorola sheet it says 0.5A).

I want to use a BC635 transistor as a switch controlled by my raspberry pi, to turn on/off a 9V DC battery powered circuit that has 3 LEDs in parallel on a breadboard.īefore connecting to my Raspberry Pi 4, is this connection setup correct?

I understand basics of electronic circuits but I am confused with how to connect my BJT transistor. Hi, this is my first question in this forum.

Reduce mathematica