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Topic: P-Channel mosfet controlling car 12v light (Read 69376 times) previous topic - next topic

majenko

You'll notice I have revised my component values since then ;)

Oh, and I also like to use a smaller value for the P-FET pullup.  It speeds up the switching off of the FET and reduces power consumption (and heat generation) during the switching period.

I have a quad board that I produce now (http://www.ebay.co.uk/itm/191074117720) based around that circuit.  The values I use are currently 470? for the P-FET pullup, 470? for the base input resistor, 10K? for the base pull-down, and 100? on the collector of the BJT.

Bittsen

BJT?

I don't see a BJT.

I really am not even sure I know what a BJT is.

majenko

Bipolar Junction Transistor - an NPN or a PNP transistor is a BJT.

MarkT


BJT?

I don't see a BJT.

I really am not even sure I know what a BJT is.

Or a search engine?!
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Bittsen


Or a search engine?!


I'm going to go off topic for a second.

What good is a search engine if it just directs people to places to BUY a product? I understand they need revenue, as greedy as they are, but if I want "information" then the search engines are becoming more useless all the time.

On topic, I searched, but when I was reading the reply that included the BJT comment I also saw a transistor call out.

I was looking at a circuit that had three resistors. And then was told to add one tot he BJT. Well, it looked to me like there IS one on the NPN transistor so I was, and maybe still am, confused.

majenko

#50
Apr 29, 2014, 06:21 pm Last Edit: Apr 29, 2014, 06:22 pm by majenko Reason: 1
This is my current version of the circuit:

It has the extra resistor (R4) and the "tweaked" resistor values.

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