Diode for continuous flow of hardware design

The freewheeling diodes are both ends of the parallel coils, which generate inductive emf at both ends of the coil as it passes through the current. When the current disappears, its inductive EMF generates a reverse voltage to the original in the circuit. When the reverse voltage is higher than the original reverse breakdown voltage, the original, such as transistor, and so on, causing damage. The freewheeling diode is in parallel at both ends, and when the current flowing through the coil disappears, the induced electromotive force generated by the coil is consumed by the circuit of the diode and coil. Protection of the other originals in the circuit.
In the circuit in reverse parallel to the two ends of the relay or inductance coil, when the inductor coil power loss at both ends of the electromotive force does not immediately eliminate
The residual electromotive force is released through a diode called a freewheeling diode. Actually, it's a diode.
It's just a continuation of this, for example, a diode or a unidirectional SCR that is reversed at both ends of the relay coil.
Why do we have to reverse a diode?
Because the coil of the relay is a large inductor, it can store electricity in the form of a magnetic field, so when he is absorbing a large amount of magnetic field when the transistor of the control relay changes from the conduction to the end of the coil power off but there is a magnetic field in the coil will generate a reverse EMF voltage up to 1000V The above is easy to penetrate the drive transistor or other circuit components, this is because the diode access exactly and reverse electromotive force direction of the reverse potential through the freewheeling diode in the form of current and off thereby protecting other circuit components, so it is generally switching speed of the diode, As the SCR circuit as the SCR generally as a contact switch to use, if the control is a large inductive load will produce high-voltage anti-EMF principle and the same as the relay. Also used on the display of the general use of degaussing relays on the coil.
Often used in conjunction with energy storage elements to prevent sudden voltage and current changes, providing access. The inductor can pass through it to provide continuous current to the load, so as to avoid the load current mutation to the effect of smooth current. In the switching power supply, a continuation circuit consisting of a diode and a resistor can be seen. This circuit is in parallel with the original side of the transformer. When the switch is off, the continuation circuit can release the energy stored in the transformer coil, prevent the induced voltage too high, penetrate the switch tube.
The general choice of fast recovery diode or Schottky diode can be used to release the reverse potential generated by the coil.

In Figure 3, when the KR is on VT conduction, the upper voltage is negative and the current direction is from top to bottom. When VT shuts down, the current in the KR is suddenly interrupted, generating an inductive potential, which is aimed at keeping the current constant, that is, to keep the KR current direction from top to bottom. This inductive potential and the supply voltage are added to the VT at both ends, which makes it easy for VT to wear. With VD, the induction potential generated by KR is shorted out, and the electric note is what you call "moving clockwise in the small circuit of the diode and relay" to protect Vt. The R and C in Figure 2 also utilize the principle that the voltage on C cannot be mutated to absorb the inductive potential. Visible "freewheeling diode" is not a real component, it is only in the circuit played the role of "continuous flow."

Attached: As an example of inductance coil, when there is a current in the coil, its ends will be generated by the induction electromotive force. When the current disappears, its inductive electromotive force produces a reverse voltage to the component in the circuit. When the reverse voltage is higher than the reverse breakdown voltage of the component, the components such as transistors are burnt out. If the coil ends in parallel with a diode (sometimes connecting a resistor), when the current flowing through the coil disappears, the induced electromotive force generated by the coils is consumed by the circuit of the diode and coil, thus ensuring the safety of the other components in the circuit.

For relays, because the relay coil is a large inductor, it can store electrical energy in the form of a magnetic field, so when it is sucked, it will store a large number of magnetic fields. When the transistor of the control relay changes from conduction to up, the coil will power off, but the magnetic field in the coil does not immediately disappear, the magnetic field will produce a reverse electromotive force, the voltage can be up to 1000v, such high pressure is easy to penetrate such as transistors or other circuit components. If we have a diode in reverse parallel to the relay, usually a resistor is strung on the freewheeling diode to prevent the loop current from being too high, because the diode's access is exactly the same as the reverse electromotive force, so that the reverse EMF can be consumed in the form of current, The purpose of protecting other circuit components is achieved.

For the SCR circuit, as the SCR generally as a contact switch to use, if the control is a large inductive load, the same will produce high-voltage back EMF, its principle and the same relay. A freewheeling diode is also used on the display, usually on the coil of a degaussing relay.

The working principle of the continuous current diode

• A typical application circuit of the freewheeling diode is given, in which the resistance r depends on the situation. When the energy storage element is on VT conduction, the voltage is negative and the current direction is from top to bottom. When VT is turned off, the current in the energy storage element is suddenly interrupted, the inductive potential is generated, and the direction is to keep the current constant, that is, always want to keep the energy storage element current direction from the top down. This inductive potential and the supply voltage is added to the VT at both ends, it is easy to make VT breakdown, for this can be added VD, so that the energy storage element can be generated by short-circuit the inductive potential, thereby achieving the purpose of protecting Vt.

The function of the freewheeling diode

• The freewheeling diode is usually used with the energy storage element to prevent a mutation in the voltage and current in the circuit, providing a power path for the reverse electromotive force. The inductor coil can pass through it to provide the continuous current of the load, so as to avoid the load current mutation, play the role of smooth current! In the switching power supply, a continuation circuit consisting of a diode and a resistor can be seen. This circuit is in parallel with the original side of the transformer.

  When the switch is off, the continuation circuit can release the energy stored in the transformer coil, prevent the induced voltage too high, penetrate the switch tube.

Note: It is also possible to make a radical understanding that the diode is turned on due to the conduction, resulting in a short-circuit state of the diode, it is also protected with the diodes in parallel with the diode on the left side (other cases are also willing to the right), usually also on the freewheeling diode again in series a resistor.

Diode for continuous flow of hardware design