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This is a useful way to verify that an IR remote control is in fact transmitting. Mostly harmless… Exploring electronics, programming and photography. Fill in your details below or click an icon to log in: Probably someone has misplaced them, when restocking. Anyway, I purchased them. Notify me of new comments via email. Under certain conditions, they will conduct electricity. To find out more, including how to control cookies, see here: Re-doing the math with these particular values gives the expected current for the LED: This datashret be useful for driving a darlington or as input to an opamp or inamp.
This leads us to our criteria — the current through a forward-biased LED is a constant; the current through a forward-biased PT varies with light. When forward-biased, the current through the photo-transistor is proportional to the amount of light. To drive the LED, it has to be above 1. You are commenting using your WordPress. It was a photo-transistor. The image sensors pick up IR! How would you go around this issue but with a phototransistor and a photodiode?
Leave a Reply Cancel reply Enter your comment here It was time to do some tests and measurements. Use your smart phone or camera. IR LED and a photo-transistor — which is which? The devices you present here do not appear to have that characteristic. Dimitar Kovachev February 2, at Sean Straw May 12, at When a LED is forward biased, it emits light while the transistor switches and amplifies the colector-emitter current if the base-emitter junction is forward biased.
Skip to navigation Skip to main content Skip to primary sidebar Skip to secondary sidebar Skip to footer Low voltage. You are commenting using your Twitter account. Not sure if your confusion about which component is which got resolved. A LED or a phototransistor?! Note that a reverse biased LED can conduct when light of a suitable wavelength is presented generally centered around the wavelength which that LED emits when normally driven.
All was fine, until the salesman at the local shop told me:. Related Posts.
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