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Topic: Attiny 45 flashing 12v globes (Read 437 times) previous topic - next topic

artois

Hi All
 I did this flasher circuit, first tried using BJT but no luck, then i found a help page on the forums where "Grumpy Mike" was involved using a FET and there was luck. The problem is there is a delay about 1/2 a sec before the lamps warm up, Is there something I can do or change please.
thanks
john   

Grumpy_Mike

I would remove that 10K from the emitter. With it you are only getting 6V to switch on the FET and that is not enough.

Wawa

The P-channel fet is drawn upside down, but connected right.

As Grumpy_Mike said, remove (short) the 10k emitter resistor.
The 10k resistor in the emitter line of the 2N3904 has less than 4.3volt across (BE drop), and so has the 10k resistor between +12 and gate.

If you intend to fade/PWM the lights, then change the 10k gate pull up resistor to 1k.
Leo..


artois

Hi all
Thanks, removed the 10k on emitter put link does the trick. As for the drawing of fet I just clicked on IRF9Z34N with RIMU and that showed up. I very seldom use fets so I would not know anyway.

anyway thanks
john

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