Re: [tlug] [OT] Any electricians / electrical engineers around?

[Godwin Stewart <gstewart@example.com>]

On Tue, 01 Jan 2008 10:31:46 +0900, Dave M G <dave@example.com> wrote:

> So, can (or should) this be built with an AC to DC converter?

Yes, as I said, you'll be supplying the circuit with 20V to 24V DC. You'll
want a power supply that can deliver roughly 250mA at this kind of voltage.

Here's the circuit diagram for one rail of LEDs:

  http://bonivet.net/misc/norton-generator.png

The "module" comprising components C3 and C4, Q2, R5 and D3-D10 is to be
repeated as many times as the number of rails you want, 6 in this case. The
rest is common to all of them.

Component values:

C1: 1000µF/16V
C2: 100µF/16V
C3: 220nF
C4: 100nF

D1: Bog standard 2.7V/1.3W Zener diode
D2: 1N4148

Q1/Q2: 2N2222A or equivalent

R1: 1 KOhm ±5% ½W
R2: 1 KOhm potentiometer (this will be the dimmer)
R3: 1.2 KOhm ±5% ¼W
R4: 270 Ohm ±5% ¼W
R5: 100 Ohm ±5% ¼W

-- 
G. Stewart - gstewart@example.com

Everything that can be invented has been invented.
               -- Charles Duell, Director of U.S. Patent Office, 1899

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