I am interested to measure the current-voltage characteristics of a diode with 10 or higher bit resolution. Is it possible with Arduino? If possible please provide the code and circuit diagram.
Hello Ujjwal,
If you look at the Arduino (specifically the mega2560 chip) it has an on-chip ADC with 10-bit resolution so you can use it. However if higher resolution is needed, you can always look for external ADC chips with either IIC or SPI interface.
All the best!
Hi Ujjwa;
To measure the current-voltage characteristics of a diode you might realize a standard circuit used in the classical lab.
In order to contol the circuit via Arduino, there are a lot of applications in the tool kit of Arduino or its equivalent devices. As Pr. Prasanna said you can use the on chip ADC or use an external one. this is so easy to implement as a basical A to D conversion circuit.
Good luck;
Quick answer - just with arduino solely, you wont get neither useful, nor precise I-V characteristics.
There are two main issues here:
First is not the conversion from analog to digital domain (with built in ADC), but the opposite way - to control the driver for your device under test (DUT). You need to have some programmable voltage or current source with sweep range and resolution matching your requirements (please state those in case you wish to get some further help).
The second problem is intrinsic exponent-like characteristics of diode. It messes up all your resolution, as if it fits at high values - it will be insufficient on lower ones, while in opposite case it may render an overkill.
If you are looking for some simple / homemade / low-cost solution, I would suggest you to make some simple sawtooth generator on ne555
http://www.circuitstoday.com/saw-tooth-wave-generator-using-ne555
with voltage range of your interest, then use a logarithmic transimpedance amplifier e.g.:
http://www.maximintegrated.com/en/products/analog/amplifiers/MAX4206.html
to get linear voltage output with exponential current of diode.
I would sugest that you look at some commercial semiconductor parameter testing kit such as the HP4155A
http://www.keysight.com/upload/cmc_upload/All/04155-90015.pdf?&cc=GB&lc=eng
Which describes in some detail how the tests work and the conditions for them.
This should tell you what you need to setup for your own application.
You could also do some Spice simulation which will help you get ballpark settings and ranges for implimentation into actual hardware.
@ Susan
It wasn't stated in question but I think you can assume, that if somebody wants to measure diode with arduino, buying equipment you proposed have big chances to land far beyond the budget ;]
Remember to use a four-wire approach in order to reduce the voltage drop over the measurement wires. You may want to control the current through the diode in short pulses in order to avoid heat up of the P-N transition area. And perhaps increase the current using a D/A converter, while measuring voltage with the A/D converter. If you only need a few measurement points you can build a discrete current-D/A with some resistors, using the I/O outputs, then you can avoid spending money on an external D/A IC.
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