wierd problem

[timothyjackson]

hi all.

I have a pic controlling some leds. It fades them on and off, through a transistor (more power). One pin will turn on/off a bunch of leds. Lots of wires.

For some reason, a cluster of leds will remin "on" even when the pic has cleared the port. On other clusters, this doesnt happen. And yesterday, this problem never existed.

When i touch the "base" leg of the transistor with my finger, its "remaining on" abnormal state turns off like it should. some clusters do this, some don't.

Theres alot of wires, and, ...... the fading on and off on these clusters affects the radio reception really badly.......extremley frustrating.....please help...

:?

 

[Jay.slovak]

I think you problem is "open collector" output pin. Because some pins (eg. RA4) have such outputs, you need to use a pull-up resistor from power to base... What kind od transistor do you use? (NPN, PNP MOSFET...).

 

[timothyjackson]

Hi jay.

Thanks for your reply.

I solved the problem. It was to do with the beiginning and end connections of the parellel clusters. The collecter was the problem.

Thanks.