Super Noob in need of assistance

[azamor2]

I have here a little desk fan that runs 3volt DC 500mA, I also have in my posession an old cellphone charger 5.0volt .7A If I rig these up together am i just asking to burn down my house. Im new to all this and i'd rather hear from experience than totally Eff myself over.
any thoughts will be appreciated. thanks!

 

[davenn]

hi there
welcometo the forums

The 3V fan would probably run ok off the 5V to some what faster. There is a risk of cooking it. An easy way to make it happier would be to put a couple of 1N4001 diodes in series with the + volts between the power supply and the fan. this would drop the 5V down to ~ 4V and the fan would have a much longer life expectancy

cheers
Dave

 

[azamor2]

Super cool because i dont want to buy batteries every 2 days for this tiny fan haha.
Thank you sir I do appreciate the help, and I'll probably have more questions in the future haha

oh just thought of another one, if i add a tiny little dimmer type knob? that any good?

 

[davenn]

your welcome

yes it would, as long as it could handle the current being drawn by the fan.
you try as an experiment a 1k variable resistor and see hiow it goes ... see if it gets warm. If I was going to do that I would use a wirewound one rather than a carbon track type ( the more common)

cheers
D

PS but if you are not interested in any sort speed control, just go with the 2 diodes much easier