What is the micro variable equivalent circuit of a diode?

What is the micro variable equivalent circuit of a diode?

Micro variable equivalent circuit refers to a circuit in which the voltage and current of the unsubstituted part remain unchanged after a certain part of the circuit is replaced by its equivalent circuit. This means that the part where the voltage and current remain unchanged is only a circuit outside the equivalent part.

Characteristics of micro variable equivalent circuit:

① The goal of the micro variable equivalent circuit is only to modify the momentum. Therefore, the equivalent circuits of NPN type and PNP type tubes are identical.

② The micro variable equivalent circuit is obtained at the correct Q point, such as when the Q point is set incorrectly, that is, when the Q point is selected in the saturation or cut-off region, the equivalent circuit is meaningless.

③ It is not possible to use a micro variable equivalent circuit to calculate the static operating point.

④ The voltage and current in the micro variable equivalent circuit are all indicated by the effective values of the communication variables. The direction of the voltage and current follows the defined direction of the network and should not be arbitrarily changed.

The Micro Variable Equivalent Circuit of diode

If there is only DC on the diode, then the volt ampere characteristic of this DC is its common volt ampere characteristic curve. If a small communication signal is superimposed on this DC, what is the connection between voltage and current for this small communication signal? Or, for this communication signal, what circuit is the diode equivalent to? This is its micro variable equivalent circuit. Of course, for this communication signal, the diode is equivalent to a resistor, which is also related to DC

Ambition diodee equivalent circuit

In a circuit, if the forward voltage drop when the diode is turned on is much smaller than the voltage of the component in series with it, and the reverse current when the diode is turned off is much smaller than the current of the component in parallel with it, then the forward voltage drop and reverse current of the transistor can be ignored to turn the diode into a switch. When a forward voltage is applied, the diode is turned on, and the forward voltage drop is 0, which is equivalent to the switch closing. When a reverse voltage is applied, the diode is turned off, The reverse current is 0, which is equivalent to the switch being disconnected.