Volt Regulated
Volt Regulated
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 36 Amp 12 Volt 138V Regulated Radio Power Supply 12V  US $65.00
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 Astron VS12M Regulated Power Supply W Volt Amp Meters US $65.00
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 33 Amp 12 Volt 138V Regulated Radio Power Supply 12V US $61.00
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 Heathkit Regulated power supply 1 to 15 volt IP 18 US $15.00
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 NEW PYRAMID PS 14KX 12 AMP VOLT REGULATED POWER SUPPLY US $62.80
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 micronta regulated 12 volt power supply US $20.00
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 MICRONTA REGULATED 12 VOLT POWER SUPPLY US $12.00
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 KENWOOD PD35 10D VOLT CURRENT REGULATED SUPPLY 35V10A US $199.95
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Help me slow down a CPU cooling fan hard wired?
I have a 12 volt CPU cooling fan that is stand alone and is hardwired to a 12v dc adapter i found around my house. The fan cools a set-top box receiver that gets hot. The fun runs great, but the problem is its full speed and too loud. What is the simplest, cost effective way to lower this speed (or voltage i guess?) It would be even better if I can regulate the speed.
1.- Find another dc adapter, let say 9vdc or 6vdc. The current capacity of the adapter has to be enough for the fan, check it out.
2.- Put a few diodes in serie with the fan. Each diode will make a voltage drop of 0.7 volts which will reduce the speed of the fan. You have to check the correct polarity of the diodes. Also the current capacity of the diodes has to be accordingly with the fan current.
3.- Put a resistance in series with the fan, the resistance value has to be small let say 10-30 ohms and the resistance power has to be enough in order to not to get burned. Power = I^2R where I is the current of the fan and R is the value of the resistance in ohms.
Choose one of the above ones.
If you know electronics you can also build a power control circuit but in that case.......you were not asking this.