Reference: https://wenku.baidu.com/view/5c3d8a5c804d2b160b4ec01d.html
In addition to conducting one-way diode characteristics, there are many features, many of the circuit is not one-way conductivity can analyze the circuit works constituted a diode, and the diode need to have more features can be able to get an accurate analysis of circuit theory .
A diode simple DC circuit
Simple diode voltage regulator circuit is mainly used for some partial DC voltage supply circuit. Characterized by: a circuit is simple, and low cost.
Simple primary regulator diode circuit with a diode voltage drop of substantially constant characteristic that a substantially constant pressure drop in the diode is turned on, the voltage drop for a silicon diode is approximately 0.6V for the voltage drop of the diode of germanium 0.2V or so.
In the circuit, three diodes in series, are simultaneously turned on as at the same time or, according to the conduction characteristics of the diodes, such that the voltage at point A when the diode is turned on, at a fixed voltage, to the role of a simple regulation.
Second, the diode temperature compensation circuit
After the PN junction voltage drop across decreased slightly with increasing temperature, the higher the temperature the greater the amount of decrease thereof, use of this feature may be utilized for temperature compensation diode pair transistors, thereby ensuring more stable operation of transistor.
In this circuit, the diodes and transistors in a PN junction will be the same results for changes in ambient temperature, so as to achieve a temperature compensation, to reduce the effect of temperature on the base current, to ensure the stability of the base current, in order to ensure stability of the entire circuit.
Third, a diode control circuit
After diode conduction, the forward resistance which varies with the current size of the size of slight variations, the greater the forward current, forward resistance, and vice versa.
FIG circuit is a diode constituted by the automatic control, also known as the ALC circuit (automatic level control circuit), it is often used in the magnetic recording device in the recording circuit.
Circuit Analysis: presentation capacitor C1 of the recording signal path, a first stage amplifier input audio signal from the recording, and is turned through VD1 C1 flows to the ground terminal, are formed on the recording signal attenuation cattle, flowing into the second recording amplifier stage the recording signal is small, thereby controlling the amplitude of the recording signal. And the presence of VD1 is turned off, in the case of OFF, no effect on the recording signal shunt, shunt for the turn-on signal recording (U1 voltage controlled diode is turned on and off).
Fourth, the diode limiter circuit
The so-called limiter circuit is to limit the size of a point in the signal amplitude circuit, the signal amplitude is large enough to allow a certain degree does not increase, when the amplitude of the signal does not reach the magnitude of the limit, the limiter circuit does not work.
V. diode switch circuit
When forward voltage is applied to the switching diode, the diode in a conducting state, on-state corresponds to the switch when the diode is reverse voltage to the diode in an off state, corresponding to the off-state of the switch.
Circuit Analysis: inductor L1 capacitor C1 connected in parallel and the circuit is a parallel resonant circuit, C2, and VD1 form a series circuit, and then and C1 in parallel, the control VD1 by the voltage V off to change the resonant circuit capacitance, thereby changing the resonant frequency .
Sixth, the diode detector circuit
Circuit Analysis: As shown, the detector circuit, the AM signal is applied to the positive electrode of the detection diode, rectifier diode works at this time detector diode in the rectifier circuit works essentially the same, so that the detection signal amplitude using the diode conduction, to give the half cycle signal AM signal, the AM signal by the frequency capacitance of the filtered carrier signal, the envelope of the positive half cycle of the signal obtained across the resistor R1, through the coupling capacitor C2, a DC component removed signal.
Seven, the relay drive circuit protection diode circuit
Internal relay having a coil structure, when power a large counter electromotive force is generated, easy breakdown driver transistor, so that a diode is connected across the relay, causing the collector voltage of the driving transistor is clamped to live, so that the protection circuit triode. The role of the RC circuit the relay circuit may Reference: https://wenku.baidu.com/view/7b95f15387c24028915fc37c.html
