(The resistance is wrong, please ignore the size, the 20K one should be about 10R) As shown in the circuit, the VD voltage is between 0.7V-0.3V. In this case, the MOS tube can be turned on when the switch is pressed. Pull down this 0.7-0.3 voltage?
to add on:
The model of the MOS tube in the picture is actually cj2302, and the on-resistance is between 50-80mR
Kobe 发表于 September 16, 2020
According to the PDF curve, when the MOS tube is turned on, it can be done when the Id current is less than 30mA.
Or replace the MOS tube with low Rds.
Hana 发表于 September 16, 2020
The MOS tube has internal resistance when it is turned on, and the voltage drop generated is related to the current.
If 0.7-0.3V can only provide current within 30mA, the MOS transistor will turn on and pull the drain to close to 0V.
Maia 发表于 September 16, 2020
The specific current is not measured. If it is a triode, we understand that it is 2 PN junctions, so the minimum voltage VCE (MOS tube is VDS) is also the conduction voltage drop of a PN junction of 0.3V. Can't MOS tube understand that? Is it calculated from the on-resistance plus the current?
