Contents
How to calculate optocoupler efficiency in a circuit?
The most convenient way of specifying optocoupling efficiency is to quote the output-to-input current transfer ratio (CTR) of the device, i.e., the ratio of the output collector current (I C) of the phototransistor, to the forward current (I F) of the LED. Thus, CTR = I C /I F.
What is the operation of a PMOS capacitor?
Summary of PMOS capacitor operation EE 230 PMOS – 8 Creating a hole inversion layer connects the source to the drain. The PMOS is “on”. For now, we connect the source to the body and apply the controlling voltage between the gate and the source.
How is the current flow of a PMOS determined?
If v DSis kept small, the current flow is “ohmic” – like a resistor. R DSdepends on the how much gate voltage is applied (determining the hole concentration in the inversion layer) and the physical dimensions of the PMOS. iD
What is the substrate rule in PMOS circuit?
The junction would likely be burned out. The PMOS substrate rule: The substrate (body) should be connected to the highest voltage in the circuit – usually the positive power supply. Then the source and drain must both be at the same or lower voltages, and it will be impossible to forward-bias the diodes.
How is the optocoupler connected to the TTL?
Here, the optocoupler LED and current-limiting resistor R1 are connected between the 5V positive supply rail and the output-driving terminal of the TTL device (rather than between the TTL output and ground), because TTL outputs can usually sink a fairly high current (typically 16mA) but can source only a very low current (typically 400µA).
How does an optocoupler work with an Arduino MOSFET?
The idea behind this schematic: when switched on, the ports are high, no current through the LED, MOSFET gate pulled low, and it’s off. Then when I make the port low, it sinks the current for the LED in the optocoupler, the gate is pulled high, and the MOSFET switches on.
Is the opto coupler a constant current source?
Your biggest potential problem is that the opto-coupler acts like a constant current source. As you turn it on it will always be current limited by the gate capacitance charging. In addition the Opto has to provide current through the 10k resistor, which to hold your device on (VGS > 2.5 V @10 A) requires 0.25 mA.