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TerraMex · 08-22-2003, 10:30 PM

> desk transformer

As in light an cellular phones? Too low output current. The best i've see was 500mA.

You could try an old HP printer power supply. If i remember correctly, the old 500 series printer had a big PS.

>Since the fan does not start up until 6 vdc, is it possible to set a
>minimum voltage for the adj. power supply. Instead of 3-24vdc,
>make it 6-24 vdc? Please help. I do not want to worry about the
>setting being too low, and have no fans.

Yes, but.

Without knowing the actual shematic of the PS, it's kinda hard.

If it was a simple LM type regulator, you'd just have to connect a proper pot, for the range that you want. Or two, and the second one would regulate the minimum voltage. The first would give the full range (maximum to minium set by user).

You can try to do the same with the PS, but you need to know the reference for that pot. Ohm value and watt rating. But that circuit will always go to 3v if you dont "mod" it.

>I would like to wire in a voltmeter into the powersupply, that will
>mount in the front of the case. I am looking for a small 0-24vdc
>voltmeter. Any ideas?

Any electronic stores have them. Just ask for a analog voltage meter display (or similar). You'd probably have to make a small adjusting circuit thou.

>do they make 12vdc - 24vdc relay switches? In other words
>when the relay is supplied 12vdc it opens a 24 vdc switch

Yes. Again, any electronic store. Just have to ask for it.

08-22-2003, 10:30 PM	#30
TerraMex Cooling Savant Join Date: Nov 2002 Location: Portugal, Europe Posts: 870	> desk transformer As in light an cellular phones? Too low output current. The best i've see was 500mA. You could try an old HP printer power supply. If i remember correctly, the old 500 series printer had a big PS. >Since the fan does not start up until 6 vdc, is it possible to set a >minimum voltage for the adj. power supply. Instead of 3-24vdc, >make it 6-24 vdc? Please help. I do not want to worry about the >setting being too low, and have no fans. Yes, but. Without knowing the actual shematic of the PS, it's kinda hard. If it was a simple LM type regulator, you'd just have to connect a proper pot, for the range that you want. Or two, and the second one would regulate the minimum voltage. The first would give the full range (maximum to minium set by user). You can try to do the same with the PS, but you need to know the reference for that pot. Ohm value and watt rating. But that circuit will always go to 3v if you dont "mod" it. >I would like to wire in a voltmeter into the powersupply, that will >mount in the front of the case. I am looking for a small 0-24vdc >voltmeter. Any ideas? Any electronic stores have them. Just ask for a analog voltage meter display (or similar). You'd probably have to make a small adjusting circuit thou. >do they make 12vdc - 24vdc relay switches? In other words >when the relay is supplied 12vdc it opens a 24 vdc switch Yes. Again, any electronic store. Just have to ask for it. __________________ "we need more cowbell."