optocoupler interface

[pranitapatil]

hi frends.
i am working with optointerupter H21A1.it is having 4 pins . i connect the 220 ohms R to the anode terminal of it and cathode is made grounded. Also i have connected the pull up R of 10 k to the collector terminal with 5 v supplyand emitter is made grounded. I observed the output in between collector and ground but it is continuosly 4.29 v even though the interupt occur. why is it so?

 

[karesz]

Hi,
Doyue connected the 220R on +5V too?
Can you measure the Led current/voltage?
Are the pins surly not changed pls?
K.

 

[IanP]

Have you connected 220Ω to +5V?
With this connection in place and nothing between diode and phototransistor, the phototransistor should pull down the voltage on it's collector o logic "L" ..

Connect mA-meter in series with 220Ω and confirm the diode's current to be around 15mA ..

Rgds,
IanP

 

[pranitapatil]

yes i have connected 5v supply to the 22o ohm.

 

[karesz]

OK,
Than measure pls LED voltage(direct on the pins) or current...
K.

 

[pranitapatil]

yes i measured the voltage across led that is coming out to be 1.7v

Added after 1 hours 2 minutes:

hey i think i should clear the terminals first. initialy i thought the terminal denoted as E as emitter.but now i think i am wrong.refer the datasheet which i posted initialy.tell me if you came to know.

 

[keith1200rs]

The terminal connections are labelled 1,2,3,4 which translate to Anode, Cathode, Collector, Emitter. The E and D markings stand for "emitter" and "detector". Confusing eh?

Also, be careful that you note the pin connections are a view of the device from the bottom (pin side) not the top.

Keith.

 

[karesz]

Hi pranitapatil,
These was the reason of my questionary in the first posting too ...
K.
I wished to quotation to make_but maked some mistake...