Increase Current on Pic's Pin.

[koossa]

Good day Picers

A slightly off topic question?

I've got a Component that requires about 60mA from my PIC's PIN.

I'm trying to figure out how to use a PNP Transistor as a switch to get a greater current from my circuit?

I know that if you use different resistors it will give you different current from the Emitter to the collector.

Is there a formula to determine what size resistor to use to get a specific amount of current through the transistor?

[mister_e]

Rb = (VCC - Vbe) / (Ic/HFE) = (5-.6) / (.06 / 100 ) = 7.1666 K = 6.8K

safer to use lower value 680 ohm is a really safe one.

[koossa]

Thank you Steve!

VCC = Input voltage
What is Vbe, Ic, HFE?

[mister_e]

Ic = Collector current
Vbe = voltage between Base and Emitter
HFE = Transistor gain, you'll find that one in the datasheet

[koossa]

Thank you!!

[Mike, K8LH]

You didn't mention if you need to sink or source current to the device? Either way, have you considered using an N-channel (sink) or P-channel (source) MOSFET instead of a bipolar transistor?

Regards, Mike

[koossa]

Hi Mike

I'm using a PNP transistor to source current.

[CocaColaKid]

Didn't you mean use a 6.8k?