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| Electronic Projects Design/Ideas/Reviews Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our experienced members find a solution. |
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Thread Tools | Display Modes |
2nd November 2005, 10:22 PM
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Transistor switch circuit
Hello all,
I've come up with a circuit that'll (hopefully) switch on both a button on a PlayStation controller and a corresponding cold cathode light using transistors. The PlayStation controller is a 3.4v signal while the voltage to the cold cathode is 12v from a separate power supply (wall wart). My questions are, will this circuit work? Must I connect the emitters of both transistors together to a single ground? Will the different voltages affect/do harm to anything? Will sharing/connecting the two grounds affect/do harm to anything? Do I need isolation between the separate 12v/ground and PlayStation signal (3.4v)/ground? Thanks. LEGEND: V+: 12v (from external power supply) GND: ground (from external power supply) CC_GND: cold cathode ground CC_V+: cold cathode V+ SW1/SW2: switch pads PS_SIG: PlayStation signal PS_GND: PlayStation ground R1/R2: current limiting resistors T1: 2N4401 T2: TIP31C |
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3rd November 2005, 04:14 AM
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just remove T1 and replace it with optocoupler...
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3rd November 2005, 05:06 AM
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Quote:
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3rd November 2005, 08:14 PM
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Okay I was looking at general purpose optocouplers and found the 4N25 and 4N35. Will either of these work for the PlayStation signal? What's the difference between the two?
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5th November 2005, 10:17 PM
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So I decided to go with the 4N35 since I couldn't find the 4N25 in the Eagle parts list. The schematic's attached. Is this correct?
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