All of this is a good argument for buying from decent suppliers who know what they're doing. Obviously, Radio Shack is not one of those.
Maybe so , but they survived more than 75 years but couldn't survive the internet.
I've used the circuit described in this article before
I am an old campaigner and I love a good campaign.So, here, my "Detector" (as D.U.T.) findings --I have the IR emitter pretty close to the detector, 0.1 inches or so.I do have a light on, so that I can see what I'm doing, which influences the results a tad.Uninterrupted, unobstructed, there is 0.8V at Vout and 1.4V when I interrupt, or obstruct, the optical path between.If I place translucent material between (esd mylar bag, old pink anti-static bag), Vout varies with the material's transmissibility.
In the dark, I imagine the collector would go much closer to the 5V rail. (When the beam is interrupted.)I'm surprised that the output doesn't go closer to 0V than 0.8V with them that close together though.How hard are you driving the emitter? 100mA?
I'm only running about 20mA through the emitter. (The "spec card" states 40mA max for this.)Changing the Vout pullup to 1kohm: obstructed Vout = 3.9V (also dark, under an old 35mm film holder) and unobstructed = 2.3V
You'd get better results with a high-power IR LED.
Likely so, but perhaps somebody else.My interest is only bringing clarity to the subject at hand.Over the years they probably used several devices presenting these pairs.My pack was pretty old. The "blister" had yellowed as well as the phototransistor encapsulant, but I opened it up for the sake of Science - to shed some badly needed light on this matter.
I think that light was shed when it was realised that 'interestingfellow' really had a photo-diode, not a photo-transistor.There wasn't actually a need for you to show the performance of your photo-transistor and low-power IR LED.
The RadioShack package that the OP's using has a phototransistor, albeit mismarked, but you can persist contrariwise all you like.
Did you bother to read Dave Evans' post, #18?
Well, that makes me feel better; I was making a mistake, just not the one I thought.So what could I do with the set I have? Or rather, a typical intended purpose?Thanks, agian, y'all!(and, no, I didn't notice the lack of transistor symbol, but I won't anymore* )