Design, construction, testing my cheap DIY spot welder 2.0 - Pt. 1 of 3

long video but rich of details to understand how to design your own prototype of spot welder machine able to work with Cu/Ni strips. All the three videos contain an explanation of the circuit, how to realize it, the final test and the conclusions.
total cost: mosfet 15€ + copper bar 10 € + IC's 8 € + case 5 € + cables 10 € + spot pen 15 € = 63 €
Project and gerber available at this link:
oshwlab.com/ro...