Pulse width modulator

[Arthur Alchin (Arthur Alchin)]

Wanted to make a dew heater controller for my home made dew heaters (nichrome wire).

The main heater for the nose of my meade lxd75 8" SN (made of nichrome wire) drawers just over 1 amp at 12.5 volts delivering about 13-14 watts which is ample for the dew beating purpose but i needed a better controller than just a 1 to 5 ohm variable pot.

Found a website called "kitstop.com.au" who sell a Pulse width Modulator that is rated 40 watts (they also have larger capacity ones). It is about $11 something for the kit or $18 something preassembled ( + postage of about $6) all you need to get is a box to put it in, a couple of appropriate plugs/sockets and a knob.

At this size it doesn't require a heatsink.

I am impressed as (from memory) it runs at 100hz with a varying pulse width of 5-100%.

I am interested in feedback from others members.

PS: mine is working extremely well.

[wasyoungonce (Brendan)]

Have a look here or here or here or mine here.

Mine never got put into the projects section...maybe it's not good enough?

[GTB_an_Owl (Geoff)]

thats funny Arthur
i just ordered 2 x units rated at 3 amps (with heat sink) for about $14 each (fully assembled with knob for pot)
just need a case and the other bits

i am also considering ordering a PC fan control unit with 4 channels rated at about 2 amps per channel to experiment with

geoff