- Jul 13, 2001
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Hi all, I've been searching google all of this morning to no avail. I have a color LCD display that I'm attaching to a computer case. The LCD requires 12v and 500ma. I'd like to be able to power up and down the display using a serial interface. I'm a VB/C++ programmer so the programming aspect I can take care of. My problem is that I'm clueless with electrical component design :-\
I found one google post that is close to what I'm looking for:
<<
1N4148 diode, qty: 2
2N3904 transistor
4.7 K ohm resistor
External 12V supply
relay with 12V coil
Connect the anode of the diode to the RTS line.
Connect the cathode of the diode to one side of the resistor.
Connect the other side of the resistor to the base of the transistor.
Connect the collector of the transistor to a +12V supply.
Connect the emitter of the transistor to one side of the coil of the relay.
Connect the other side of the relay coil to ground on the external power
supply.
Connect the power supply ground to the computer ground.
Connect the second diode's cathode to the collector of the transistor.
Connect the second diode's anode to the emitter of the transistor.
Turn everything on, and toggle your RTS bit. You'll find that when the bit is
high, the relay is off. The transistor should be able to drive a 12V coil of up
to 200mA. If you're certain everything's working, you can use the computer's
power supply instead of an external power supply.
>>
The problem with this solutions is that its 200mA not 500mA. Is there anyway I can adapt this to make it work or does anybody have another solution?
I appreciate your time!
Obsidience
I found one google post that is close to what I'm looking for:
<<
1N4148 diode, qty: 2
2N3904 transistor
4.7 K ohm resistor
External 12V supply
relay with 12V coil
Connect the anode of the diode to the RTS line.
Connect the cathode of the diode to one side of the resistor.
Connect the other side of the resistor to the base of the transistor.
Connect the collector of the transistor to a +12V supply.
Connect the emitter of the transistor to one side of the coil of the relay.
Connect the other side of the relay coil to ground on the external power
supply.
Connect the power supply ground to the computer ground.
Connect the second diode's cathode to the collector of the transistor.
Connect the second diode's anode to the emitter of the transistor.
Turn everything on, and toggle your RTS bit. You'll find that when the bit is
high, the relay is off. The transistor should be able to drive a 12V coil of up
to 200mA. If you're certain everything's working, you can use the computer's
power supply instead of an external power supply.
>>
The problem with this solutions is that its 200mA not 500mA. Is there anyway I can adapt this to make it work or does anybody have another solution?
I appreciate your time!
Obsidience