DIY dew heaters.

[malc-c]

I'm looking into making some dew heaters using Ni-chrome Wire. I'm looking for someone who has any commercial heater bands and access to a DVM who can tell me what length the heater is and what resistance each one is.

[Reggie]

BC&F, 53cm, seems to wander between 18-22ohms.

no name (either from modern astronomy or flo), 39cm, 23.2ohms.

that is the length from the base where the nichrome goes into, to the end of the semi-hard strip that I believe is there to keep the loop from shorting.

[barkis]

Do a search on the web for Nichrome wire.

It can be bought in reels, and the resistance values vary depending on what you want to achieve power wise.

The resistance is measure Ohms per metre of wire, so using Ohms Law, you can work out the power rating of each dew strap you make, when you know the length required.

Volts divided by Resistance = Current.

Volts Squared divided by resistance = Watts.

Volts times Current = Watts

Current x Volts = Resistance.

So knowing two values, you can calculate the Unknown.

Ron.

[LeoLion]

I think you will find all you want on Nichrome Dew Heaters on Dave Ratledges pages here TELESCOPE MAKING . The PWM controller from Maplin should be this one Panel Mounted Speed Regulator Module : Motors & Gearboxes : Maplin Electronics . Hope this helps

[malc-c]

Reggie, that's exactly what I'm after/

Ron, thanks for the links and info - This was the issue, in that once I knew the resistance of a commercial product I could then order the right ohm/meter reel of wire

Leo, thanks for the link. I have purchased a controller which I'm experimenting with (just used a 52 ohm power resistor as a test and it works OK)

[beamish]

Malcolm would this help ??

Heaters

it's what I used, successfully I may add

[malc-c]

Malcolm would this help ??

Heaters

it's what I used, successfully I may add

Another one bookmarked - Thanks