Opto Isolator

Thread Starter

libbylou28

Joined Sep 12, 2016
7
I am a student teacher and I am trying to get to grips with this circuit. I have come in half way through a course and a student has designed this and I want to check it will work. The emitter circuit is fine I just need to check that the receiver circuit is correct!!

My knowledge is ok but need some help with this. upload_2016-9-12_21-41-39.png
 

kubeek

Joined Sep 20, 2005
5,772
Hi and welcome to the forum.
I see three problems in the circuit, first of all I cannot see any optocoupler in that circuit, so I don´t really know what you´re asking. Second thing is that the C08 is only good up to 5.5V, while the battery is 9V. Third thing is that D3 is missing a series resistor and will burn out very fast.
 

Thread Starter

libbylou28

Joined Sep 12, 2016
7
Hi and welcome to the forum.
I see three problems in the circuit, first of all I cannot see any optocoupler in that circuit, so I don´t really know what you´re asking. Second thing is that the C08 is only good up to 5.5V, while the battery is 9V. Third thing is that D3 is missing a series resistor and will burn out very fast.
Hi and welcome to the forum.
I see three problems in the circuit, first of all I cannot see any optocoupler in that circuit, so I don´t really know what you´re asking. Second thing is that the C08 is only good up to 5.5V, while the battery is 9V. Third thing is that D3 is missing a series resistor and will burn out very fast.
Thank you for the response. The opto coupler will be put into the 3 pin terminal block at the bottom of the circuit on the right. I see what you are saying about D3 and will change the battery voltage. But it's not far off being right??
 

kubeek

Joined Sep 20, 2005
5,772
I still don´t understand, an optocoupler typically has an LED on one side and a phototransistor on the other side, so I would expect two sets of two pins that should convey the signal. Frankly I have no idea what the bottom half of that circuit is supposed to do. Could you ask your student to actually specify the optocoupler and draw it in the diagram, and also say what is the purpose of it? So far I don´t see anything that would need an optocoupler nor what it should be doing.
 

Thread Starter

libbylou28

Joined Sep 12, 2016
7
I still don´t understand, an optocoupler typically has an LED on one side and a phototransistor on the other side, so I would expect two sets of two pins that should convey the signal. Frankly I have no idea what the bottom half of that circuit is supposed to do. Could you ask your student to actually specify the optocoupler and draw it in the diagram, and also say what is the purpose of it? So far I don´t see anything that would need an optocoupler nor what it should be doing.
Will do I'll get back to you in the morning and thanks again for your input.
 

Thread Starter

libbylou28

Joined Sep 12, 2016
7
Why is pin G3 connected to V+?
No idea!! The bottom of the circuit confuses me I know the circuit is based on a project board you can buy. I know the infra red receiver part number is 55-0620 and is a vishay TSOP4838 Infrared Receiver 38kHz any ideas would be welcome!!
 

Alec_t

Joined Sep 17, 2013
12,812
If a TSOP4838 connects to C4 it will require a ground (i.e. B1-) connection. No such connection is available via CN1/3 with CN1 wired as shown.
 

Thread Starter

libbylou28

Joined Sep 12, 2016
7
If a TSOP4838 connects to C4 it will require a ground (i.e. B1-) connection. No such connection is available via CN1/3 with CN1 wired as shown.
Ok that makes sense although not sure which pin on CN1 to connect to ground. Thank you by the way you have been very helpful!
 
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