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Date: 07/18/01 at 8:47 AM
Posted by: John Dunn - Consultant
E-mail: ambertec@ieee.org

In Reply to: long range IR Xmitter posted by Jeff Tieman on 07/18/01 at 8:33 AM:

Hi, Jeff.

Your description doesn't quite sound right to me. I sounds like the MOSFET is connected backward.

What I'd imagine you'd have is an n-channel power MOSFET with its source at ground, its drain connected to the cathode of the LED, the LED's anode connected to one end of the current limiting resistor and the other end of that resistor connected to a positive Vcc. Then your gate drive requirement would be zero volts for the LED off and enough positive voltage to ensure turning on the MOSFET for the LED on.

Does this help?

John Dunn - President
Ambertec, Inc.
ambertec@ieee.org

Follow Ups:

  Re: long range IR Xmitter Jeff Tieman   Posted at: 07/18/01 (5)

  Re: long range IR Xmitter John Dunn - Consultant   Posted at: 07/18/01 (4)

  Re: long range IR Xmitter Jeff Tieman   Posted at: 07/18/01 (3)

  Re: long range IR Xmitter John Dunn - Consultant   Posted at: 07/19/01 (2)

  Re: long range IR Xmitter Jeff Tieman   Posted at: 07/20/01 (1)

  Re: long range IR Xmitter Hap   Posted at: 12/19/01 (0)

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