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vir
vir
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The Rds of your 2N7000 when Q1 is in cutoff should be ~1.5~2 ohms or perhaps a little more, which is a little high compared to power MOSFETS switching big currents, but your 20 mA indicator LED current will generate less than 1 mW inside M1 so even with its rather large 312.5°C/W Rth(j-a), you will raise junction temperature by a minuscule amount. You are fine.

The Rds of your 2N7000 when Q1 is in cutoff should be ~1.5 ohms, which is a little high compared to power MOSFETS switching big currents, but your 20 mA indicator LED current will generate less than 1 mW inside M1 so even with its rather large 312.5°C/W Rth(j-a), you will raise junction temperature by a minuscule amount. You are fine.

The Rds of your 2N7000 when Q1 is in cutoff should be ~2 ohms or perhaps a little more, which is high compared to power MOSFETS switching big currents, but your 20 mA indicator LED current will generate less than 1 mW inside M1 so even with its rather large 312.5°C/W Rth(j-a), you will raise junction temperature by a minuscule amount. You are fine.

Source Link
vir
vir
  • 29k
  • 1
  • 26
  • 64

The Rds of your 2N7000 when Q1 is in cutoff should be ~1.5 ohms, which is a little high compared to power MOSFETS switching big currents, but your 20 mA indicator LED current will generate less than 1 mW inside M1 so even with its rather large 312.5°C/W Rth(j-a), you will raise junction temperature by a minuscule amount. You are fine.