12v switch?

oscarBravo

Hi all,

I have a requirement for a fair number of compact fast ethernet switches, 4- or 5-port. They need to be pretty small, and - most importantly - they have to work on a 12v DC power supply.

3Com used to have an OfficeConnect range that ran on like 6-24v or something, but I don't think they're available anymore.

Any suggestions?

Static M.e.

I know D-Link Do small 5 Port Switchs, think they run on 7.5v but worth checking out

oscarBravo

Thanks, but the 12v requirement is a firm one - these will be in an environment where they may be powered by 12v lead-acid batteries. That means they have to be able to run at 13.8v (float-charging voltage) and down to about 10v (battery nearly empty voltage).

Capt'n Midnight

Look up 7805 regulator chip - this will give 5V if the voltage sensing pin is tied to ground. As that pin only takes ~ 2mA you can put an LED in series with it to get higher voltages depending on the colour of the LED ( red for about 6.5 V etc. )

bushy...

If your going to run it from say 10.5v --> 13.8v, you could be better off to go with a switch that takes about 8v and use a regulator, maybe a 7806 / 7808 / 7809 or an lm340 ....bit more trouble but better than using switches that accept a wide range of input but are scarce,if you get stuck you easily find a replacement

Capt'n Midnight

http://www.cpemma.co.uk/7volt.html - 7 volt trick - for quiet fans too

see also http://www.cpemma.co.uk/diodes.html

http://www.rason.org/Projects/regulator/regulator.htm

oscarBravo

Maybe the regulator trick is the way to go. Will these dump much heat when running at 13.8v?

Sponge Bob

a low voltage and very cheap switch here , maybe it could run on 5v USB or PS2 port power instead of a regulated 9v or 12v

http://www.sunsway.com.hk/products/5-port-switch-2.html

and same

http://www.komplett.ie/k/ki.asp?sku=303997