newbie LED lamp setup

[airbrush]

How would i go about doing this....I want to make a lamp consisting of rows of LEDs and use a switch of some kind(like a dimmer switch) to control them. The more you turn the switch, the more rows of LEDs it would light up.
It would be nice too if they would glow and get brighter rather than just turn on at full intensity(ie: row one would be at full intensity, row 2 would be half, row 3 quarter intensity...)
How would I go about doing this??

 

[Russlk]

It would be a lot easier to run them all in series and use PWM to control the brightness. Check out 555 timer circuits.

 

[airbrush]

as the post says....newbie here.....so what is PWM and 555 timer circuits

 

[Dr.EM]

Ok, PWM stands for pulse width modulation. A 555 is an integrated circuit, which is described as a universal timer. In the application you suggested, you would use it as an oscillator (ie, something that goes between 2 states at a set rate). So, what you would be doing is switching the LEDs on and off very fast. Now, by adjusting the PWM, the LED can be made to appear brighter or dimmer, according to how wide the pulses are. If more of the pulses are mostly high, the LED is on more of the time in relation to off, so it appears bright, and vica versa.

 

[fredsm]

You oughta find something suitable at:

**broken link removed**

Look under "Timers and Drivers" on the
second page.

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