Re: circuit design help: momentary switch activates/cancels electronic switch



Fred Bloggs wrote: 

Okay, thanks for all the replies.  Sorry to change things up on
you...but like I said early on, this is a learning experience for me.
It has occured to me that I don't want to worry about contact bounce
and that in reality, this will fit my application much better if there
are 2 momentary switches.  pressing one of them turns the system on and
pressing the other turns the system off.  i can probably adapt this
setup somehow from some of the provided circuits, so I will look into
it.  this might actually simplify the circuit too i would think.


IF your load is inductive, non-resistive, or capacitive then something like this would be better:
View in a fixed-width font such as Courier.

.
.    12VDC>-------+----+---+-------+-----+-------+
.                 |    |   |       |     |       |
.                 |    |   |       |     | 12VDC |
.                 |    |   |       |     --RELAY---
.                 |    |   |       |    |\      COM|
.                 |  [10K] |       -    |/         |
.                 |    |   |       ^    |\         |
.                 |    |   |    1N4001  |/      NO |
.                 |    |   |       |     ----------
.                  >|  |   |       |     |       |
.             2N3906|--+---|-[10K]-+-----+       |
.                  /|      |             |       |
.                 |        o             |       |
.                 |      -| SWon         |       |
.                 |        o             |       +-------+
.                 |        |             |       |       |
.                 |        |             |       -       |
.                 |        |             |       ^       |
.                 |      [2.2K]          |    1N4001    LAMP
.                 |        |             |       |       |
.                 |        |          ||-        +-------+
.                 +--------+-------+--||<IRF510  |
.                 |        |       |  ||-        |
.                 |        o      ===    |       |
.               [10K]    -| SWoff 0.01U  |       |
.                 |        o       |     |       |
.                 |        |       |     |       |
.                 +--------+-------+-----+-------+
.                         ---
.                         ///


Allowing for pressing both switches simultaneously, make this change:
        View in a fixed-width font such as Courier.

..
..    12VDC>-------+----+---+-------+-----+-------+
..                 |    |   |       |     |       |
..                 |    |   |       |     | 12VDC |
..                 |    |   |       |     --RELAY---
..                 |    |   |       |    |\      COM|
..                 |  [10K] |       -    |/         |
..                 |    |   |       ^    |\         |
..                 |    |   |    1N4001  |/      NO |
..                 |    |   |       |     ----------
..                  >|  |   |       |     |       |
..             2N3906|--+---|-[10K]-+-----+       |
..                  /|      |             |       |
..                 |        o             |       |
..                 |      -| SWon         |       |
..                 |        o             |       +-------+
..                 |        |             |       |       |
..                 +--------+             |       -       |
..                 |                      |       ^       |
..                 |                      |    1N4001    LAMP
..                [1K]                    |       |       |
..                 |                   ||-        +-------+
..                 +--------+-------+--||<IRF510  |
..                 |        |       |  ||-        |
..                 |        o      ===    |       |
..               [10K]    -| SWoff 0.01U  |       |
..                 |        o       |     |       |
..                 |        |       |     |       |
..                 +--------+-------+-----+-------+
..                         ---
..                         ///

.

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