#Ttl optical isolator sparkfun how to#
#Ttl optical isolator sparkfun series#

#Ttl optical isolator sparkfun how to#

How to get Technical Assistance from a Technical Support Moderator.Any suggestions would be greatly appreciated. Add 2 jumpers to connect the output of A to input of B, input a signal to A and you get no output signal from B. Input a signal to circuit in diagram B and you get an output signal. Input a signal to circuit in diagram A and you get an output signal. I've checked voltages and connections many times. Why does this circuit not work? I understand the Opto Isolator board has 2 circuits and is simplified in the diagram and there may be no conceivable reason to use the circuit in Diagram C, but that still does not explain why it doesn't work. Diagram C shows a NON-working circuit of a Opto Isolator board using one power source for both input and output for the first stage and a Opto Isolator using the output of the first stage and separate power source for the second stage output. Diagram B shows a working circuit of a Opto Isolator board using 2 power sources, one for input and one for output.

Here is the Diagram of the 3 circuits and a recap of the issue.ĭiagram A shows a working circuit of a Spark Fun Opto Isolator break out board using 1 power source for both input and output. If this can't be understood without the attachment, maybe an Admin can help me out with privileges to attach the jpg

I would rather not get distracted on why I would want to do such a thing before understanding why the output of an Opto Isolator can not be used as the input for another Opto Isolator.

#Ttl optical isolator sparkfun series#

Separately each circuit works, in series they do not. This feeds the second Opto which has its own power on the output side. Basically 1 Opto which has common power for input and output. Well, I can't attach the file so this may be difficult to interpret. What you put into the IN pins, will be replicated on the the OUT pins, but at the higher voltage (HV).In the attached image, Diagram A shows a working circuit of a Spark Fun Opto Isolator break out board using 1 power source for both input and output. We threw some transistors on this compact board to correct the inversion. Great for use in noisy circuits where signal lines require electrical isolation.Ī normal LED opto-isolator will invert the logic of a signal. This breakout board uses the ILD213T optoisolator and discrete transistors to correct the logic. This board will isolate the systems, creating a type of electrical noise barrier between devices. We often use this board to allow a microcontroller control servos or other motors that use a higher voltage than the TTL logic on the (3.3V or 5V) micro, and may cause electromagnetic interferance with our system as the motors turn on and off. This allows the low-voltage side to control a high voltage side. This IC has two LEDs and two photodiodes built-in. This board electrically isolates a controller from the high-power system by use of an opto-isolator IC. This board is helpful for connecting digital systems (like a 5V microcontroller) to a high-voltage or noisy system. This is a board designed for opto-isolation.