Re: Help with pulse width modulator
I do a lot of gigging at night on small, public lakes. The problem is that the spot light I use to see fish is so powerful that I light up the water front houses and freak people out. If I could control the brightness I could probably spook less fish and people. I found this PWM for a decent price. Can anyone see any problems that might arise from using this with a 12 V, 100W Q bean spot light. I plan on running the light on full power for 10 min every hour to burn the halogen light filament clean. What would be the best way to enclose this circuit and the best way to mount it? Any ideas?
Thanks
http://www.electronickits.com/kit/complete/motor/CKMX033.htm
Well your 12V 100 watt bulb will draw 8 amps steady state. This is within the limits of the unit. On start-up it will draw about 10 times that. The inrush current for an incandescent bulb is typically 10 times rated bulb current or in this case 80 amps. This is for a relatively short period of time, so the unit MAY survive this. When you put it in a sealed box, it will get HOT, and that will further reduce the current handling capacity of the unit. Again, it may or may not survive this. It depends on what part is used to switch the current on and off. Also, the design targets MOTORS, not LAMPS. The behavior of motors can be much different than lamps. One final concern... This unit will likely interfere with any radios in the area, and will likely interfere with any fishfinders that you may have operating on the boat.
I looked up the design for the higher current versions and they use an IRF1404 which is rated for about 140 amps at elevated temperature. This is probabaly sufficient IF they use the same part (one each) in this design. I would still be a little suspicious. It is your money, and you should not hurt anything with it IF you fuse the supply line to the lamp with about a 15 amp fuse and use a sufficient sized wire (#14 or larger diameter [Smaller number]). also, again the heat build-up is a concern.
I personally would not extend the wires on the Pot. Doing may be a recipe for disaster on this sort of design. More potential for interference from the device and to the device, as well as mechanical issues.
TerryMSU
