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As with (almost) any MCU,This is due to leakage through the ESP8266 oncircuitry of your WeMos D1 board has protection diodes on its inputsMCU. This means that thereEven when your MOSFET is a diodeturned off, connecting the positive supply rail (3MCU remains connected 3.3V) to the output pin D1 (and - although it does not matter in this case - there is also another diode connecting D1 to ground).

Current will Some current can flow, from the 3.3V supplyinput, out through this diodepin D1, through the 10k resistor, through the 676k resistor, to ground. This pulls the gate of the MOSFET up, allowing more current to flow (but due to the forward voltage drop of the diode, the gate voltage remains limited and perhaps the MOSFET does not turn on enough for the MCU to boot up).

A possible solution would be to use a high-side switch instead (using a P-channel MOSFET), whose gate you pull down using a second (N-channel) MOSFET. This is illustrated in an answer to another question on this site.

As with (almost) any MCU, the ESP8266 on your WeMos D1 board has protection diodes on its inputs. This means that there is a diode, connecting the positive supply rail (3.3V) to the output pin D1 (and - although it does not matter in this case - there is also another diode connecting D1 to ground).

Current will flow, from the 3.3V supply, through this diode, through the 10k resistor, through the 676k resistor, to ground. This pulls the gate of the MOSFET up, allowing more current to flow (but due to the forward voltage drop of the diode, the gate voltage remains limited and perhaps the MOSFET does not turn on enough for the MCU to boot up).

A possible solution would be to use a high-side switch instead (using a P-channel MOSFET), whose gate you pull down using a second (N-channel) MOSFET. This is illustrated in an answer to another question on this site.

This is due to leakage through the circuitry of your MCU. Even when your MOSFET is turned off, the MCU remains connected 3.3V. Some current can flow from the 3.3V input, out through pin D1, through the 10k resistor, through the 676k resistor, to ground. This pulls the gate of the MOSFET up, allowing more current to flow (but due to the forward voltage drop of the diode, the gate voltage remains limited and perhaps the MOSFET does not turn on enough for the MCU to boot up).

A possible solution would be to use a high-side switch instead (using a P-channel MOSFET), whose gate you pull down using a second (N-channel) MOSFET. This is illustrated in an answer to another question on this site.

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As with (almost) any MCU, the ESP8266 on your WeMos D1 board has protection diodes on its inputs. This means that there is a diode, connecting the positive supply rail (3.3V) to the output pin D1 (and - although it does not matter in this case - there is also another diode connecting D1 to ground).

Current will flow, from the 3.3V supply, through this diode, through the 10k resistor, through the 676k resistor, to ground. This pulls the gate of the MOSFET up, allowing more current to flow (but due to the forward voltage drop of the diode, the gate voltage remains limited and perhaps the MOSFET does not turn on enough for the MCU to boot up).

A possible solution would be to use a high-side switch instead (using a P-channel MOSFET), whose gate you pull down using a second (N-channel) MOSFET. This is illustrated in an answer to another question on this site.