In this video I do the third Maxitronix 10in1 Electronic Project Lab project: Diode Experiment.
When I looked at the resistor on the bottom I thought it was red – brown – black – gold which would have been 21Ω but I think I misread brown and that was actually purple which would be 27Ω which stacks better with the two measurements I made both of which said 27Ω.
In the video we examine the forward voltage of our germanium diode and get various readings. Typically a germanium diode should be around 0.3V versus silicon diodes which are usually around 0.7V.
On the FNIRSI component tester the Ir is the “reverse current”, also known as the “leakage current”. This is the small amount of current which flows through the diode when it is reverse biased (that is, basically, connected the wrong way around).
I asked ChatGPT a few questions about diodes and their specifications which you can read here: Germanium Diode Forward Voltage if you’re at all interested in such things. Of course you should be doubly suspicious of anything you read on the internet. :)
The really amazing learning for me in this experiment was how hot the germanium diode got versus the lamp, which was so surprising. Just goes to show how good an idea it is to actually do experiments and measure things! The thermal imager we used was the UNI-T UTi260B.
Also I think I’m coming around to the view that an oscilloscope is a pretty poor voltmeter. My oscilloscope is an MSO5074 70MHz 4 Channel MIXED SIGNAL OSCILLOSCOPE and I love it but I think in future I will limit my use of the oscilloscope to situations where I’m actually dealing with some sort of oscillator. I think simple digital multimeters would have been better test equipment to use for the kinds of readings I was trying to take in this experiment.
I hope you enjoy the video. Stay tuned for the upcoming projects. If you’re interested in seeing them don’t forget to subscribe!
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