Or switch that NPN to a PNP and re-arrange the circuit
accordingly.  Or you could use two NPN transistors.
Not sure if either of these are the "right" way to do
it, but they'll both work fine for an LED.

If all you're driving is an LED, I'm sure the inverter
IC can handle that.

Cheers.


--- rixy04 <rixy04@VVALLEY.COM> wrote: > Just tie the
collector to + and put your 300R and
> LED in the emitter to ground.
> Rick
>
> Robert Rothe wrote:
>
> > I'm still learning, so please forgive my
> ignorance.  I have an IR detection module (an old
> radio shack one) that detects IR signaling at about
> 40 kHz.  It drives its data line LOW when a signal
> is received.  I have it hooked up to shut OFF an LED
> when a signal is present using this circuit:
> >
> >                                       VCC 5Volt
> >                                        +
> >                                        |
> >               o-------------------------
> >               |                        |
> >               |                        |
> >               |                       .-.
> >               |                       | |300R
> >               |                       | |
> >               |                       '-'
> >               |                        |
> >               |                        |
> >               |                        |
> >               |                        V LED
> >               |                        -
> >               |                        |
> >               |                        |
> >             2 o                        |
> >                                ___   |/
> >        IR   1 o--------------o|___|--| NPN n2222
> >        Recvr                   1K    |>
> >                                        |
> >             3 o                        |
> >               |                        |
> >               |                        |
> >               |                       ===
> >              ===                      GND
> >              GND
> >
> > I wanted to invert the process so that the LED
> lights when a signal is present so I tried this
> circuit:
> >
> >                                       VCC 5Volt
> >                                        +
> >                                        |
> >               o-------------------------
> >               |                        |
> >               |                        |
> >               |                       .-.
> >               |                       | |300R
> >               |                       | |
> >               |                       '-'
> >               |                        |
> >               |                        |
> >               |                        |       LED
> >               |
> +------->|------+
> >               |                        |
>     |
> >               |                        |
>    ===
> >               |                        |
>    GND
> >             2 o                        |
> >                                ___   |/
> >        IR   1 o--------------o|___|--| NPN n2222
> >        Recvr                   1K    |>
> >                                        |
> >             3 o                        |
> >               |                        |
> >               |                        |
> >               |                       ===
> >              ===                      GND
> >              GND
> >
> > This seemed to work OK except that I get some odd
> indications on the LED that IR is being detected.
> I suspect they were there in circuit #1, but
> couldn't be seen.  (I grounded the metal can of the
> detector module.  Putting a sunglass lens over the
> module helped a bit, too)
> >
> > Are these (especially the second) the right way to
> do this?
> >
> > My second question is, if I decided to just use an
> inverter (ie, 7404), I'm unclear how to determine in
> the data sheet how much current it (the 7404) can
> sink.
> >
> > Sorry for the simple questions.  Any help would be
> greatly appreciated.
> >
> > Rob
> >
> > --
>
> --
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>

=====
MJ Brush
LeftClick.ca Internet Media Services
mbrush@[NOSPAM]leftclick.ca

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