Building a Test Load (4-30V 0-4A)

Let's build a DIY test load to test USB chargers and other power supplies. It can operate at 4 to 30V supply voltage and draw an adjustable current from 0 to 4A. Warning: it can get very hot, risk of fire or burns!

The FNB58 USB tester I'm using:
https://www.fnirsi.com/products/fnb58?sca_ref=9216013.ntkg5GeG0R&utm_source=af&utm_medium=ref&utm_campaign=9216013

My test load on my website
https://danyk.cz/zatez2_en.html

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