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Looking for a new Linear Light Dimmer

R

RV-4

Well Known Member
Hello All

I'm in need of a new Light Dimmer for my -4 as the one I have right now ( 1.5 Amps ) is not powerful enough to power the inst. lights I have ..

I looked at these ones but was told as they are PWN that they may create noise

https://www.aircraftspruce.com/catalog/elpages/brit-01-7a-dimm.php?clickkey=4042

https://www.aircraftspruce.com/catalog/elpages/4channeldimmer13-15799.php?clickkey=4042

I've seen a few on the web but they were really expensive :eek:

So if anyone has one for sale or knows where I could find such a beast, I will appreciate it.

Thanks

Bruno
[email protected]
 
Thanks Bryan

I'll send this to my friend who's the electronic guru among us and see what he thinks of it.

For $8 it is hard to go wrong with that.

Bruno
 
Last edited:
RV-4 said:
Hello All

I'm in need of a new Light Dimmer for my -4 as the one I have right now ( 1.5 Amps ) is not powerful enough to power the inst. lights I have ..

I looked at these ones but was told as they are PWN that they may create noise

https://www.aircraftspruce.com/catalog/elpages/brit-01-7a-dimm.php?clickkey=4042

https://www.aircraftspruce.com/catalog/elpages/4channeldimmer13-15799.php?clickkey=4042

I've seen a few on the web but they were really expensive :eek:

So if anyone has one for sale or knows where I could find such a beast, I will appreciate it.

Thanks

Bruno
[email protected]
Click to expand...

how many amps do you need?
 
Thank you Walt for the reminder, I totally forgot about checking with Vans...:eek:

Yes, they have the same type of Dimmer I'm looking for.

Thanks again

Bruno
 
Linear Regulators...

there are 5 amp linear regulators see https://www.ti.com/lit/ds/symlink/lm338.pdf
and the circuits are really simple. And the part is about $2. The big challenge is power dissipation. Let's say you are doing 4 amps and dropping 14.2 volts down to 6.2 volts...

The power dissipated in the linear regulator will be (14.2 - 6.2) volts * 4 amps = 32 WATTS !
without a heat sink the device will have a temperature 35 degrees C above ambient PER WATT, so 32 * 35 ... means it will be 1120 degrees C above ambient. Well no, it won't get there, it will blow long before that. Max op temp is just 125C.

This is why my 7 amp bench variable power supply weighs about 25 pounds. Heat Sinks!

This is the basic reason while PWM regulators are attractive. They are a switch... on and off hundreds or thousands of times per second. The eye can't see the flicker, and the power lost in heat is orders of magnitude less.

Now, maybe your load won't pull 4A at 6.2 volts. Then the heat situation may be only half as bad.
 
blaplante said:
Yes PWM can be noisy.

I just checked out this one https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html
$8
and at least at low load of a couple amps, I didn't hear any noise on a nearby AM radio tuned off station. Usually if they are noisy, it will make a real ruckus on AM.

Not all PWM units are noisy. But no guarantee that this thing would be quiet driving 10 amps. For the price... worth a try?
Click to expand...

get it quick, allelectronics is closing up shop soon.
 
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