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fan speed switching?

M

mike

Jan 1, 1970
0
Being completely clueless on circuit design I thought I'd try this NG to
seek some inspiration!

I have a standard 12v fan I'd like to toggle between two different speeds
using a momentary action switch. The fan speed is currently being changed
using a 62 ohm 7 watt ceramic resistor to drop the supply power.
I really havent got a clue where to begin.
Any pointers gratefully received!


Mike.
 
R

Rich Grise

Jan 1, 1970
0
mike said:
Being completely clueless on circuit design I thought I'd try this NG to
seek some inspiration!

I have a standard 12v fan I'd like to toggle between two different speeds
using a momentary action switch. The fan speed is currently being changed
using a 62 ohm 7 watt ceramic resistor to drop the supply power.
I really havent got a clue where to begin.
Any pointers gratefully received!


Mike.

Connect the switch across the resistor. When the switch is closed,
the fan runs fast. When the switch is open, the fan runs slow.
If you still find this confusing, I'd strongly recommend looking
up some basic tutorials - they're all over the place - try
http://www.google.com and search for "electronics tutorial" or
some such. From time to time, other regulars post links to
basics sites, too.

Good Luck!
Rich
 
C

cpemma

Jan 1, 1970
0
Rich said:
Connect the switch across the resistor. When the switch is closed,
the fan runs fast. When the switch is open, the fan runs slow.
If you still find this confusing, I'd strongly recommend looking
up some basic tutorials - they're all over the place - try
http://www.google.com and search for "electronics tutorial" or
some such. From time to time, other regulars post links to
basics sites, too.
Easy with a SPST toggle switch, but with a single *momentary* switch you'll
need something like a flip-flop driving a relay switch across the resistor,
with anti-bounce on your momentary switch.

There are some circuits on Terry Pinnel's site, including
http://dspace.dial.pipex.com/terrypin/Images/ToggleMoment.gif
 
M

mike

Jan 1, 1970
0
cpemma said:
Easy with a SPST toggle switch, but with a single *momentary* switch you'll
need something like a flip-flop driving a relay switch across the resistor,
with anti-bounce on your momentary switch.

There are some circuits on Terry Pinnel's site, including
http://dspace.dial.pipex.com/terrypin/Images/ToggleMoment.gif

Thanks so far people. The circuit on the quoted url seems ideal.
The fan is rated at 2.4w (200ma?) so maybe I'll need to use the relay
circuit as well.
Looks like I have some reading to do!

Mike.
 
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