hi
im trying to make my own fume extractor
ive got this for it
extendable Air duct from PC case
9v power adapter and socket
1 80cm fan 12v
1 red led for power indicator
switch
some mesh
carbon filter
9v battery for testing
im not using a circuit board just soldering it all together
now ive got the led working fine with the switch its when i add the fan the led stays on but the fan dont spin, but it works fine on it own. i guess im not wiring it up the right way.
any help would be great
thanks
fume extractor
-
Simon (Webmaster)
- Site Admin
- Posts: 173
- Joined: Tue Jan 29, 2008 7:05 pm
- Location: Nottingham, UK
- Contact:
Re: fume extractor
Hi.
How are you connecting the fan and LED to the power supply? By the sounds of it you might be connecting them in series. You need to connect the fan in parallel with the LED, both to the supply. HOWEVER you will need a resistor in series with the LED unless it is a type that already has a current limiting resistor built in. For a standard red, yellow or green with a 9V supply you need a 360 ohm resistor. For any other colour LED you will need a different value.
Connect the resistor in series with the LED. Connect these across the battery (LED should light). Connect the fan across the battery in parallel with the LED & resistor. The LED and fan should now both work.
How are you connecting the fan and LED to the power supply? By the sounds of it you might be connecting them in series. You need to connect the fan in parallel with the LED, both to the supply. HOWEVER you will need a resistor in series with the LED unless it is a type that already has a current limiting resistor built in. For a standard red, yellow or green with a 9V supply you need a 360 ohm resistor. For any other colour LED you will need a different value.
Connect the resistor in series with the LED. Connect these across the battery (LED should light). Connect the fan across the battery in parallel with the LED & resistor. The LED and fan should now both work.