powering lilliput lcd from opus psu .

**robutek** · 02-19-2004, 01:29 AM

I have searched and found out how to power the lcd from the psu, and went out to radio shack to buy a barrel plug that had fit into the jack from the screen. But the problem I ran into was, on the barrel plug, you can screw off a piece of it, and there was 2 connectors to solder to, one that was long and went around the outside of the plug, and one that was short that was in the center. Now, which one is + and -, or positive and ground? Thanks.

**shchua** · 02-19-2004, 04:33 AM

The terminal connected to the outside of the plug should be connected to GND. The terminal at the centre of the plug should be connected to +12V. After soldering the wires, test the plug for correct polarity with a multimeter BEFORE plugging it into the Lilliput. The centre of the plug (hole) should be +12V with reference to the outside (sleeve) of the plug.

If you want to be ultra-careful, temporarily put a 47 ohm resistor in series with the +12V supply before plugging it into the Lilliput. This will prevent the Lilliput from smoking if you have the polarity wrong (the current is limited to 250 mA). The power LED should light up. If not, unplug it quickly and double-check your wiring again.

**Azh2004** · 06-13-2004, 04:51 PM

Originally Posted by shchua

The terminal connected to the outside of the plug should be connected to GND. The terminal at the centre of the plug should be connected to +12V. After soldering the wires, test the plug for correct polarity with a multimeter BEFORE plugging it into the Lilliput. The centre of the plug (hole) should be +12V with reference to the outside (sleeve) of the plug.

If you want to be ultra-careful, temporarily put a 47 ohm resistor in series with the +12V supply before plugging it into the Lilliput. This will prevent the Lilliput from smoking if you have the polarity wrong (the current is limited to 250 mA). The power LED should light up. If not, unplug it quickly and double-check your wiring again.

thanx a lot m8 ive set it up and its working fine.