Timeline for IR Led & Phototransistor pair bandwidth issue
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 21, 2015 at 2:34 | answer | added | user76064 | timeline score: 0 | |
| Dec 11, 2014 at 6:18 | history | edited | ythey | CC BY-SA 3.0 |
schematic, bandwidth problem, datasheets
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| Dec 10, 2014 at 18:35 | vote | accept | ythey | ||
| Dec 7, 2014 at 21:58 | comment | added | ythey | It is just a prototype design to use for further design process. IR LED is connected to NPN AND gate, and it just works fine(I've already tested it about more than 20 times.) The purpose is to transmit, and receive information through IR&PT pair. | |
| Dec 7, 2014 at 21:50 | comment | added | George Herold | Is that the whole circuit? No caps anywhere? could be leakage/ RF pickup/ voltage ripple.. Do you have a 'scope? | |
| Dec 7, 2014 at 21:03 | comment | added | ythey | i don't remember the exact value; but, Vbe of BC847b was about 1.3V. Actually, everything seems normal in the presence of IR wave; however, the circuit continues to operate when IR light goes off (I even tried by putting circuit to a box in a dark room). Why does PT continue to conduct if there is no light source near to it? @GeorgeHerold | |
| Dec 5, 2014 at 15:54 | comment | added | George Herold | What's R4 for? Why not connect the 2nd transistor right to the photo-transistor (PT) emitter? What's the voltage at the PT emitter.. (maybe you have it in backwards?) | |
| Dec 5, 2014 at 13:01 | answer | added | WhatRoughBeast | timeline score: 1 | |
| Dec 5, 2014 at 10:42 | history | asked | ythey | CC BY-SA 3.0 |