robertgzzzt
- Jun 26, 2013
- 98
- Joined
- Jun 26, 2013
- Messages
- 98
I'm obviously new here, so let me start off by saying I'm a total rookie at electronics. I just got into this a few weeks ago, when I decided to take on the task of building a very detailed 1/350 scale model of the star ship Enterprise from Star Trek. This model is almost 3 feet long when completed, and is designed to be lit, so I decided that I would build my own LED circuits instead of buying an expensive pre-built kit, which has now introduced me to an equally interesting hobby in electronics.
I'm going to need four circuits. One of them is a simple blinker circuit, a strobe circuit, a chaser circuit (10 LEDs lighting in sequence), and a fader circuit. I've already got the chaser, it's good to go. I've built it on the breadboard and tested it thoroughly. Only thing to do now is transfer it to a circuit board.
It's this simple little blinker that I'm having trouble with. I can build it, no problem. It's a simple circuit to build with the 555 timer, but here's my problem. When I wire in more than one LED in parallel (anode to anode thru a resistor and cathode to ground), the LEDs get progressively dimmer the more I put in. After wiring in just three LEDs, the third one is just barely visible compared to the 1st one. I'm powering the circuit with a 9v 1amp wall wart. I was under the impression the 555 timer could output up to 200 milliamps. These LED's current rating is only 20mA, so what's the deal?
My circuit is basically the same as the schematic in the link below, minus "C2", and with different values for C1, R1 and R2, and I'm using 220ohm resistors for the LED(s). What do I need to do to get 8, nice bright LEDs, in parallel, going on for 1 second and off for 1 second with my 9v wall wart?
http://startingelectronics.com/beginners/start-electronics-now/tut5-555-LED-flasher/
I'm going to need four circuits. One of them is a simple blinker circuit, a strobe circuit, a chaser circuit (10 LEDs lighting in sequence), and a fader circuit. I've already got the chaser, it's good to go. I've built it on the breadboard and tested it thoroughly. Only thing to do now is transfer it to a circuit board.
It's this simple little blinker that I'm having trouble with. I can build it, no problem. It's a simple circuit to build with the 555 timer, but here's my problem. When I wire in more than one LED in parallel (anode to anode thru a resistor and cathode to ground), the LEDs get progressively dimmer the more I put in. After wiring in just three LEDs, the third one is just barely visible compared to the 1st one. I'm powering the circuit with a 9v 1amp wall wart. I was under the impression the 555 timer could output up to 200 milliamps. These LED's current rating is only 20mA, so what's the deal?
My circuit is basically the same as the schematic in the link below, minus "C2", and with different values for C1, R1 and R2, and I'm using 220ohm resistors for the LED(s). What do I need to do to get 8, nice bright LEDs, in parallel, going on for 1 second and off for 1 second with my 9v wall wart?
http://startingelectronics.com/beginners/start-electronics-now/tut5-555-LED-flasher/