I started a similar project, I wired up 4 car automotive bulbs (i bought 8) to an attiny and using shift registers i make them blink in sequence, I used TIP31's though and it works nicely providing you put 12-14v through (the voltage drop makes it visibly dimmer), i got them blinking real pretty, I tried two IRF's n mosfets as well, they worked almost identically in brigtness, even fading in and out like an LED, I think i used a 1k bleed resistor though but i'm sure it worked identically, i've got to build the damn thing anyway it's a christmas display.
I want to do something similar tot he OP and want to know if this (crudely drawn) circuit is correct
Took a while to decipher that drawing, but I think it looks OK.
I'd drop resistor 2 to around 330? ish, and have resistor 3 at 10K?. I also like to add a resistor in between the collector of the BJT and the gate of the FET - just a couple of hundred ? - just to limit any current spike when the BJT turns on.
majenko:
Took a while to decipher that drawing, but I think it looks OK.I'd drop resistor 2 to around 330? ish, and have resistor 3 at 10K?. I also like to add a resistor in between the collector of the BJT and the gate of the FET - just a couple of hundred ? - just to limit any current spike when the BJT turns on.
Thanks.
The drawing is crude because I drew it as I will put it on my breadboard. I tried VBB but there didn't seem to be a way to add a mosfet to the components.
I will wire one of these up tonight and see if I don't blow a component or two.
@Bittsen
Look at response 24.
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.
BJT?
I don't see a BJT.
I really am not even sure I know what a BJT is.
Bipolar Junction Transistor - an NPN or a PNP transistor is a BJT.
Bittsen:
BJT?I don't see a BJT.
I really am not even sure I know what a BJT is.
Or a search engine?!
MarkT:
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.
This is my current version of the circuit:
It has the extra resistor (R4) and the "tweaked" resistor values.