There was no "Thermal sensor," I don't know where you got the idea there would be one. This is more about the 555 and the mosfet, not about imaginary thermal sensors.

@@DanBullard I have seen dozens of circuits with either Z 44 or BC 547 or 555. But each assembly uses a temperature sensor, which, when it heats up, turns on the fan. Your montage, how does it work ? How does the fan start without a temperature sensor ? Am văzut zeci de montaje, fie cu Z 44, fie cu BC 547 sau 555. Dar fiecare circuit folosește un senzor de temperatură, care, atunci când se încălzește, pornește ventilatorul. Montajul tău, cum funcționează ? Cum pornește ventilatorul fără senzor de temperatură ? Bye !

@@John_Smile If my circuit was so simple, and I used more than enough words, it should have been obvious. I push a button. I didn't copy anyone else's circuit, this is my own tool for blowing steam or stink out of my bathroom. What kind of food are you eating that causes high temperatures when you go to the bathroom?

@@DanBullard I understand. You place the order via the On/Off button. I want to use it to control the fan of a welding machine (inverter). When welding, the inverter has a fan, which cools certain parts. But the fan runs non-stop. Now it's 3℃ outside and the fan is still running. I want to set it to start working, from 40℃ up. Goodbye ! Temperature controlled Fan Using IC555 Timer kzfaq.info/get/bejne/f76jrMeUu5aXeXk.html How to make Fan control Temperature Sensor circuit using Thermistor kzfaq.info/get/bejne/rs6coM2Al7HKpHk.html

@@DanBullard This is the welding machine to be modified . kzfaq.info/get/bejne/rZ-DqbdkrpyaqJs.html