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Using 12v at base of transistor

ntewinkel

Hi all,

 

I'm thinking of using a transistor in a car circuit, to switch a light depending on the state of another light.

 

So it will be 12v as the signal at the base of the transistor.

 

I have a bunch of pn2222a transistors, and I can't figure out from the datasheet what the maximum means for that. It seems to be a reverse maximum (ie, don't let the output be more than 5v over the base voltage).

 

So the question is - is it possible to switch a transistor like that using 12v at the base?

 

Thanks!

-Nico

 

ps, I know I can easily do this using relays, but those take up more space, and I'd prefer to avoid the mechanical bits.

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  • 0

    Computers have gotten so big that they have become well suited to emulating PROMs.  Something like bool LUT [0xFFFF];  You need a minimum address space of 2^n, where n is the number of input states.  Your bus width is dependent on the number of outputs, eight should be plenty.  You can make a coupla fns that emulate the turn signal and brake pedal inputs through the keyboard and one that emulates the various lights you have on the screen.  Your program's MPD upon receipt of a new keypress updates the array, which causes, potentially, a change on the light models shown on the screen.  I do not know why MK and co have such trouble with this method, it is a fairly common one.  I do note, in passing, that the UK was quite slow to phase out leaded gas.  Basically combinatoric logics can be supplanted with LUTs

     

    If there is a soln that works but for lightbulbs, not LEDs, you could use some kind of comparator circuit to detect when it intended to flash the bulbs and use it to drive your amplifier to power your LEDs.

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  • 0

    Computers have gotten so big that they have become well suited to emulating PROMs.  Something like bool LUT [0xFFFF];  You need a minimum address space of 2^n, where n is the number of input states.  Your bus width is dependent on the number of outputs, eight should be plenty.  You can make a coupla fns that emulate the turn signal and brake pedal inputs through the keyboard and one that emulates the various lights you have on the screen.  Your program's MPD upon receipt of a new keypress updates the array, which causes, potentially, a change on the light models shown on the screen.  I do not know why MK and co have such trouble with this method, it is a fairly common one.  I do note, in passing, that the UK was quite slow to phase out leaded gas.  Basically combinatoric logics can be supplanted with LUTs

     

    If there is a soln that works but for lightbulbs, not LEDs, you could use some kind of comparator circuit to detect when it intended to flash the bulbs and use it to drive your amplifier to power your LEDs.

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  • 0 in reply to D_Hersey

    To understand why the trivial state machines you can model with reasonably sized  arrays of look up tables consider how you might implement a delay or a counter such as you would use for debouncing the inputs of Nico's problem.

    When complex systems are modeled in a primarily state machine environments like Stateflow (a MATLAB add on) the model relies on hierarchical state machines with complex transitions as well as the ability to perform arithmetic  - these are not simple in LUTs.

     

    But you can always confound us with a suggestion (schematic)  for a functional LUT based controller that costs less and is easier to develop and debug than an AVR image

     

    MK