15461Re: [Electronics_101] Re: Point me into the right direction please.
- Feb 1, 2005On Tuesday 01 February 2005 02:31 am, rtstofer wrote:
> Take your LED flasher example. You can look for 555 timer circuitsEven that's making things too complicated...
> on the internet. A single 555 will make one LED flash. What should
> the second do? Turn on when the first turns off? Well, any single
> transistor inverter will do that. Voila' Two flashing LEDs.
> Start simple, get one LED to flash using the 555. Then, get aNah. If you wire up one LED and resistor so that it's on when the output of
> 2N2222 transistor or most any NPN device. Connect the emitter to
> ground, connect a 1K ohm resistor between your power supply and the
> anode of the LED (the long lead) and connect the cathode of the LED
> (the lead near the flatted edge) to the collector lead of the
> transistor. Now, connect a 1K resistor between the output of the
> 555 and the base of the 2N2222. That's it. A simple inverter.
> Assuming you have a 5V power supply the LED will light up. It won't
> be very bright because the 1K resistor in series with the LED is too
> large. But, it will work.
the 555 is grounded, then wire up another one so that it's on when the
output is high, you don't need the transistor inverter!
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