GPIO - high side switching an LED

[nekrutnikolai]

I can't seem to figure out how to high-switch an LED for a matrix that I'm building. It needs to be high-switchable.

I tried building a Sziklai Pair circuit but it would not with the GPIO as the GPIO isn't strictly an on/off switch. It seems to be too sensitive, I can turn the led on or off using my finger.

Could y'all please point me in the right direction.

[drgeoff]

I can't seem to figure out how to high-switch an LED for a matrix that I'm building. It needs to be high-switchable.

I tried building a Sziklai Pair circuit but it would not with the GPIO as the GPIO isn't strictly an on/off switch. It seems to be too sensitive, I can turn the led on or off using my finger.

Could y'all please point me in the right direction.

I've been in electronics for more than half a century and never before encountered the term "Sziklai Pair". Googled it and found that yes I have used that configuration.

Need more detail (ie schematic) of what you have tried that did not work.

[boyoh]

I might be wrong with this , but it might be like a Darlington Pair configuration. So it might be very sensitive

To lower the sensitivity try a 4k7 resistor from base to ground. Or try other value resistors ( Not to low )

Regards Boyoh

[pcmanbob]

Hi.

If you want a high side driver for an LED try this circuit.

[nekrutnikolai]

Hi.

If you want a high side driver for an LED try this circuit.

Thanks for the reply.

Would it be possible to power it from an external 5V power supply as I don't want to risk damaging the GPIO, the led's need about 500mA.

[nekrutnikolai]

Hi.

If you want a high side driver for an LED try this circuit.

Thanks for the reply.

Would it be possible to power it from an external 5V power supply as I don't want to risk damaging the GPIO, the led's need about 500mA.

I realized that I can actually power the pi from the GPIO, and the schematic of the circuit that you provided works like a charm.