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

[bcroe at juno.com]

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.

Bruce Roe
17 Feb 2003 "Marteney, Steve" <Steve_Marteney at DRSOptronics.com> writes:
> Seems like you (or whoever) missed a decimal place in the above 
> subject
> line.  The Fairchild 2N2222A can carry currents up to 500mA and has 
> a
> collector current abs max rating of 1.0A.  The biggest problem is 
> its ~300
> Hfe requiring ~2mA of bias current to get that much current out of 
> it.  Some
> logic families can't do it (like trying to use an HC11 output 
> directly which
> can only source/sink approx 500uA.)
> 
> I would not be so hasty in steering someone away from the 2N2222A 
> with
> inaccurate data.
> 
> Steve
> 
> -----Original Message-----
> From: Phil Lamovie [mailto:phil at injec.com]
> Sent: Monday, February 17, 2003 9:38 AM
> To: List for general do-it-yourself EFI talk
> Subject: [Diy_efi] Re: A 2N2222A can handle up to 50mA 
> 
> 
> 
> 
> Automotive relays need 180 to 250 mA pull in current.
> 
> They can hold at half to a third if you care to P/H
> 
> I would suggest something a little more robust like a
> BD139  NPN 80 volt 1100 mA and solid without a heatsink
> for this purpose.
> 
> 
> HTH
> 
> phil
> 
> 
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://www.diy-efi.org/mailman/listinfo/diy_efi
> 
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://www.diy-efi.org/mailman/listinfo/diy_efi
> 


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi