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wagiminator / ATmega-Soldering-Station

T12 Quick Heating Soldering Station
https://oshwlab.com/wagiminator/z-solderingstation-smd-v2
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Some questions about P+ #20

Closed ChillTerry closed 2 years ago

ChillTerry commented 2 years ago

image the P+ net actually directly connects with GND, is that correct? hope to get a reasonable answer, thanks

wagiminator commented 2 years ago

No, it doesn't. Connections are marked with a junction dot: https://www.autodesk.com/products/eagle/blog/top-10-tips-draw-next-schematic-design-like-pro/

ChillTerry commented 2 years ago

thank you so much, I've got it, and I see that compare to the low version, you add D4 as a voltage regulator in Version 2.7, may I ask where is this idea comes from?

wagiminator commented 2 years ago

I added that to protect the MOSFET. The Zener diode D4 limits the voltage between the gate and source of the MOSFET to about 18V. Since the maximum gate-source voltage of the MOSFET is 20V, but this is exceeded at higher supply voltages of the soldering station, this could lead to damage to the MOSFET in the long term without the diode.

ChillTerry commented 2 years ago

thank you so much!