TI-H: IR LEDs and phototransistors

To: ti-hardware@lists.ticalc.org
Subject: TI-H: IR LEDs and phototransistors
From: Greg Hill <gregh@xmission.com>
Date: Wed, 29 Apr 1998 10:32:02 -0600 (MDT)
Delivered-To: ti-hardware-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: ti-hardware@lists.ticalc.org


I was thinking more about the IR phototransistors last night, and I think
I remembered something. Or maybe I made it up, but I thought I'd share it
anyway.

Like I said earlier, I think phototransistors are like ordinary trasistors
except that they can be activated by an electrical signal at the base
*and* by an IR signal shining in. But I think I remember something about
using the third pin to set the bias level. Maybe it allows the designer to
determine what level of IR intensity is required to make the thing turn
on..?

-- 
Greg Hill
greg-hill@bigfoot.com
www.comports.com/link

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