Affordable variable bench power supply - with external power source

Hello guys!
I wanted to build a cheap... I mean affordable variable power supply.
To make it really... cheap, I plan to use an external power source, something any of us have around the house. Let's see how this goes.

A big THANK YOU to all my patrons, especially to: Max Rice and Anthony Ortenzi.

If you are a nice lad and want to donate to me on Paypal, here you go: [email protected]

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Schematics:
power supply schematic: https://i.imgur.com/3CrwMeI.jpg
Potentiometers schematic: https://i.imgur.com/fu69FpN.jpg
PD trigger module + DC jack schematic: https://i.imgur.com/InR34jX.jpg

Components list:
80W buck/boost converter: https://s.click.aliexpress.com/e/_DdA...
Volt/ammeter 4 digit: https://s.click.aliexpress.com/e/_DFO...
Potentiometers 1K+100K: https://s.click.aliexpress.com/e/_DBr...
Binding posts: https://s.click.aliexpress.com/e/_DFU...
Potentiometer knobs 6.35mm: https://s.click.aliexpress.com/e/_DBV...
Potentiometer knobs 6mm: https://s.click.aliexpress.com/e/_DkN...
PD trigger module (a): https://s.click.aliexpress.com/e/_Dlh...
PD trigger module (b): https://s.click.aliexpress.com/e/_DFt...
5.5mm power jack (2.1/2.5mm): https://s.click.aliexpress.com/e/_DCe...

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