Dew Strip

[wookie1965]

http://www.dewbuster.com/heaters-330ohm-resistors.html

Following this guide I made a dew strip yesterday for my Tal 100rs. The strip measures 15" long I used bare copper like the guide says and 20 x 0.6 watt 330 ohm resistors. then attached 6 amp insulated cable to one of these

 http://www.ebay.co.uk/itm/DC-BARREL-PLUG-2-1-x-5-5-mm-TO-SCREW-TERMINALS-POLARITY-MARKED-PACK-OF-1-/272267778437?hash=item3f646c9985

It feels a lot hotter than my nichrome strip. Have I messed up having a bit of trouble with the calculations thanks.

[jazza]

Let's see, you have 20 330 ohm resistors connected in parallel:
1/Rtot = 1/R1 + 1/R2 + ...
So Rtot = 16.50 ohm

P = V^2/R
I'm assuming you're powering using 12V so 
P = 8.72 watts total or ~ 0.6 watts per cm.

I think nichrome is around 0.3 watts per cm so your home-made one should be twice as warm.

How were you powering it?
Note the website says:

Quote

Also, this type of heater can not be used without a controller as it would get too hot.

 

[wookie1965]

Thank you that is probably why I was powering it from one of these

http://www.ebay.co.uk/itm/12V-DC-5A-CCTV-Cameras-POWER-PSU-ADAPTER-2-1mm-4-WAY-SPLITTER-UK-3pin-Power-Cord-/400569415133?hash=item5d43cc35dd

I have got one of these,  http://www.ebay.co.uk/itm/12V-8A-PIR-Sensor-LED-Strip-Light-Switch-Dimmer-Brightness-Adjustable-Controller-/272041617645?hash=item3f56f1a8ed

Looks like I am going have to power it from the battery instead, thank you so much.

[jazza]

There's no reason I can think of why you couldn't plug the dimmer into the power adaptor the same way you would to the battery if you wanted to.
 

[wookie1965]

Thank you thank you just worked that out works perfectly now brilliant. 

[mapstar]

Well done Paul

[wookie1965]

Just now, mapstar said:

Well done Paul

Cheer`s Damian means a lot from you.

[gtis]

On 18/10/2017 at 12:18, wookie1965 said:

 

 http://www.ebay.co.uk/itm/DC-BARREL-PLUG-2-1-x-5-5-mm-TO-SCREW-TERMINALS-POLARITY-MARKED-PACK-OF-1-/272267778437?hash=item3f646c9985

I used them when I installed my cctv and cat5 cable