Re: Strange problem with STAMP and transistor switches!

On 2005-10-22, cgwiita@xxxxxxxx <cgwiita@xxxxxxxx> wrote:
> I've built a paddle-shifter controller for the electronically
> controlled transmission on my car, but it seems to be having a bizarre
> issue that came about after about a month of use operating properly.
>
> Basically, there are two shift solenoids, solA and solB, and one lockup
> solenoid. All three are electronically identical, being 10-15ohm
> solenoids. They are activated by 12v signal coming from the control
> unit (as the solenoids are grounded in the transmission)
>
....

> 1K
> ___
> .-|___|-o------o +12V
> | |
> | |< E NTE11
> o----B|
> | |\C
> |/C |
> IN oB| NTE12 |
> |>E o------o Solenoid
> | |
> | -
> .-. ^ 1N4001
> | | |
> 150 | | |
> '-' |
> | |
> '-------o
> |
> ===
> GND


with a V(CE)sat of 1V and a dissipation of 750mW the NTE11 can only handle
750mA continuous.

replace the NTE11 with a transistor that's rated for 1.5A continuous.

this'll probably mean something in TO126 or TO220 outline, and possilby a
heatsink. I'd use a BD682 because they are reaadily available here.

Bye.
Jasen
.