[Diy_efi] A 2N2222A can handle up to 50mA

[David Gravereaux]

bcroe at juno.com wrote:

>Personally I'd use a good FET output, easily available with 
>200V rating and an insulated tab.  Infinite current gain, you 
>can reduce the power supply to a zener diode.

11 cents (in bulk) for a TO-92 2N2222A vs. ~$2.50 for a TO-220 FET output
driver.  Arrange it in a darlington if you want more base gain and stay
with the cheap stuff.  It's just a switch and either it's off or
saturated.  There's minimal heat from a saturated transistor -- aka
class-D.  It's running it linear where you need to concern yourself about
vce drop equaling heat dissipation (mostly).
--
David Gravereaux <davygrvy at pobox.com>
[species: human; planet: earth,milkyway(western spiral arm),alpha sector]

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