2021.5.25 Booster circuit simulation and explanation

【This video is for educational purposes only, not for production promotion purposes.】

Consider the operation of the kacher circuit.

Don't rush to the conclusion of how it works, think slowly step by step.
Even if it is slow, if you repeat it over and over again, you will be able to understand it immediately.

The positive and negative poles of the power supply V1 are connected to the circuit.
Power supply V1 is a DC power supply.
There is a conductor path between the positive and negative poles of the power supply.
Immediately after connecting the power supply V1, there is only one path that is not disconnected.
The path connects the power supply, resistor R1, the base of the transistor, and the emitter.

It sounds easy, but it's important to have a deep understanding of this starting point.
It is assumed that the voltage of the circuit when the power supply V1 is not connected is 0 volt.
That assumption seems obvious, but the meaning of this 0 volt is very complicated.
However, the state before the circuit worked is ignored by most developers.
For example, one of 0 volts is when there is no voltage. It is also 0 volt when there is a voltage in the opposite direction and it is almost balanced. All you need to remember is to represent both of them. So 0 volt is not unique.
If the voltage is assumed to be 0 volt when no power supply is connected to the circuit, it is necessary to pay attention to whether the voltage exists or is balanced in the environment where the circuit is placed. As the experiment continues, it becomes clear that it is closer to the fact that the voltage is gradually balanced.

Immediately after connecting the power supply V1, the voltage of the path gradually increases.
The situation can be confirmed by the waveform of V (n004).
The voltage rise stagnates near 0.6 volt.
The operation of the transistor starts around 0.6 volt.

The path, power supply, coil L1, transistor collector, and emitter that were cut off by the transistor are connected.
The coil L1 operates at the same time as the connection.
Coil L1 slightly reduces the voltage of the rising circuit.
This is because when a voltage is applied to the coil, a magnetic field is generated and pushes the voltage back.
This causes the path voltage to drop below 0.6 volts.
After that, the operation of the transistor stops again, and at the same time, the operation of the coil L1 also stops, but the voltage of the coil L1 pushed back gives a voltage to the circuit.
Therefore, the voltage of the power supply, resistor R1, the base of the transistor, and the path of the emitter increases the speed of ascent as the voltage of coil L1 is applied. Thus again the circuit exceeds 0.6 volts and operates the transistor at a higher voltage than last time. Coil L1 also operates again, and a stronger magnetic field is generated than last time, pushing back the voltage of the circuit strongly. The strongly generated magnetic field is related to the coil L2. When a positive voltage is applied to the coil L1, a negative voltage is generated in the coil L2. One of the terminals of coil L2 is connected to the base of the transistor, and the negative voltage of coil L2 is applied to this contact. When the negative voltage of the coil L2 exceeds 0.6 volts, the diode D1 operates and the diode and the coil L2 become conductive. At this time, the current flowing from the resistor R1 to the base of the transistor is pushed back by the surge current immediately after the diode D1 conducts. Therefore, no voltage is applied to the base of the transistor and the operation of the transistor stops. At the same time, the operation of the coil L1 also stops, the coil L2 also stops, the negative voltage of the coil L2 drops, and the operation of the diode D1 also stops. By stopping this diode D1, the voltage of the power supply, the resistor R1, the base of the transistor, and the path of the emitter rises with the voltage of the coil L1. And when it exceeds 0.6 volts again, the transistor operates, and the coil L1, coil L2, and diode D1 operate. In this way, the transistor stops again. This operation is repeated. Since the voltage discharged after the coil L1 is stopped vibrates and drops, this operation is repeated continuously in a very short cycle during the vibration of the coil L1. After the voltage of coil L1 drops completely, diode D1 will not operate for a while. In this way, the operation of diode D1 has both a short cycle and a long cycle. The coil L1 doubles as the primary coil of the transformer and the choke coil of the circuit on the primary coil side. It is also possible to operate with the polarity reversed by changing the circuit configuration.