Doubt about the pnp transistor

[exapod]

If you use a pnp transistor for switch the npn that drives the leds is the pwm signal inverted? i mean if the pwm of the uc pin is high for 20us the led will be off for 20 us or i am wrong?

[Stephanie]

You are correct, when pin 5 is high, the IR leds are off, and when pin 5 is low, the IR leds are on.

[exapod]

So if i use the v1,2 software but control only one led with a npn it will not work??

[Stephanie]

If you want to do that then you'd have to modify the software to invert the signal on that pin. It's not too difficult, just changing a few lines in the main file.

I actually had to do this on my most-recent TV-B-Gone build, not for the IR LEDs but for the visible LED as my build had the visible LED wired to ground instead of Vcc.

[exapod]

Thank you for the help.