LED Resistor help

[jleslie48]

Originally Posted by kf4jqd

DO NOT use direct AC to feed those LED's! I have used Atlas snap on relays to isolate the LED's. Use a seperate power supply! I use an old notebook pc's power supply. Then Use a 7805 regulator to drop the 13.8vdc to 5vdc. Then I use a 1000 Ohm (1K) resistor. This will make the LED last for many many years to come.

The 7805 regulator is a very easy device to use. It has 3 wires coming out of it. The first is the input-middle is ground or negative- the output is 5vdc.

One last thing. AC can cause the LED to flicker. AC also burns out LED's, even if the voltage is correct.

Andy

Excellent implementation! I love the reuse of those old power supplies. I've got about a dozen of them from all the old kids toys, broken cordless phones, modems, et al. The regulator is the key.

[kf4jqd]

Originally Posted by jleslie48

Excellent implementation! I love the reuse of those old power supplies. I've got about a dozen of them from all the old kids toys, broken cordless phones, modems, et al. The regulator is the key.

Save those walwart power suppolies! A 9dv at 300mA will power alot of LED's! Here's a link for a novice to build a simple 5vdc power supply! Simple 5V power supply

Andy

[jleslie48]

Originally Posted by kf4jqd

Save those walwart power suppolies! A 9dv at 300mA will power alot of LED's! Here's a link for a novice to build a simple 5vdc power supply! Simple 5V power supply

Andy

OK, just to clarify, I believe these are the radio shack parts that are necessary for the project:

RadioShack.com - Cables, Parts & Connectors: Component parts: Transistors & analog ICs: +5V Fixed-Voltage Regulator 7805
RadioShack.com - Cables, Parts & Connectors: Component parts: Capacitors & resistors: 10µF 35V 20% Radial-lead Electrolytic Capacitor
the 100nF part (see below)
RadioShack.com - Cables, Parts & Connectors: Component parts: Capacitors & resistors: 100µF 35V 20% Radial-lead Electrolytic Capacitor

and a mounting board:
RadioShack.com - Cables, Parts & Connectors: Component parts: Breadboards & IC sockets: Pre-Punched IC-Spacing Perfboard

Now my limited education in bread boarding tells me two warning signals:

1) the uF capacitors have one lead longer than the other.
- that means the longer side is positive (just like the leds) which means it
makes a difference which you wire them up.

2) I suck and u,n,p
- on the 100nF 100 nano ferrid capacitors, I always mess up in converting from micro to nano, to pico, to ...
so it is this part:
RadioShack.com - Cables, Parts & Connectors: Component parts: Capacitors & resistors: 0.1µF 50V Hi-Q Ceramic Disc Capacitor Pk/2
or this one:
RadioShack.com - Cables, Parts & Connectors: Component parts: Capacitors & resistors: 0.001µF 500V 20% Hi-Q Ceramic Disc Capacitor


and the last but not least, part are the LED's themselves with there corresponding resistors:

RadioShack.com

RadioShack.com - Cables, Parts & Connectors: Component parts: Capacitors & resistors: 1K ohm 1/2W 5% Carbon Film Resistor pk/5

[kf4jqd]

Radio Shack still sells electronic parts? LOL

Andy KF4JQD

[jleslie48]

Originally Posted by kf4jqd

Radio Shack still sells electronic parts? LOL

Andy KF4JQD

Even CEO Can't Figure Out How RadioShack Still In Business | The Onion - America's Finest News Source