How does a composite switch work?

The basic working principle of a composite switch is to connect a thyristor in parallel with a magnetic latching relay. The composite switch has the advantages of thyristor zero-crossing switching at the moment of turning on and off, and has the advantage of no power consumption of the contactor switch during the normal turn-on period.

A composite switch is a device used to control the switching of capacitors. The thyristor and the relay contact are used in parallel, and the thyristor realizes the voltage zero-crossing input and current zero-crossing cut-off, and the mechanical contact passes through the continuous current, so as to avoid the conduction loss of the thyristor and the inrush current when the capacitor is put in. Since both power electronics and mechanical contacts are used, they are called compound switches.

Compound switches have been widely used due to their capacitors' characteristics of no inrush current input and current zero-crossing removal. The thyristors in composite switches are only used at the moment of input and cut-off, so there is usually no need to select thyristors according to the rated current, and the thyristors do not need to add heat sinks. In the composite switch, both thyristors and relays are used, so the structure becomes more complex, the cost is relatively high, and the thyristor is also relatively easy to damage due to the sensitivity of the thyristor to overcurrent, overvoltage and DV DT.

In practice, composite switch failures are mostly caused by thyristor damage. In order to ensure the reliability of the composite switch, the withstand voltage of the thyristor in the compound switch should reach more than 2500V, and the maximum allowable peak current should also exceed the maximum current that may occur in the circuit, but to achieve this, it is necessary to increase the cost. Unfortunately, in order to reduce costs, many manufacturers use thyristors that do not meet the above requirements, making the reliability of composite switches very poor.

If the thyristor in the compound switch is eliminated, and the contact of the mechanical switch is accurately closed or disconnected at the required moment through precise control means, it becomes a synchronous switch, and the capacitor can also be switched without inrush current and arc breaking. Since the synchronous switch omits the thyristor, the cost is reduced and the reliability is improved, but the development and design are difficult.

Compound switch is simply a combination of mechanical switch and electronic switch, both have the advantages of the two but also inherit the shortcomings of the former, the biggest advantage is that it is cheap, with the decline of the module, the compound switch will not have a long way to go. HKCS series thyristor capacitor switching module is very cost-effective.

The combination switch is a multi-function combination switch used to control lighting and light signal devices and some other accessories. It is usually a joystick type and is mounted on the steering column under the steering wheel for easy operation by the driver.

Usually, a combination switch is divided into two handles and a button:

Left handle. It's a light control switch. Control turn signals, headlights, and other lights.

Before turning, turn the handle back and forth according to the direction of the steering wheel to turn on the left and right turn signals respectively. Clockwise is a right turn, counterclockwise is a left turn. At this time, the corresponding turn indicator in the instrument cluster should also be on.

When the steering wheel returns to the center after the new car turns, the handle will automatically return and the turn signal will automatically turn off.

Some cars have a lane change gear, and a slight forward (or rear) pull the handle to turn on the turn signal, and automatically return to the position after letting go.

Its end can be twisted around the axis of the handle to control other lights, also in three gears:

Neutral off, all lights out. It should be blocked here during the day.

1. For night use: except for the headlights, other lights are fully on, including: instrument lights, front lights, rear lights, license plate lights, etc.

2. Headlights on: The low beam lights are on, and the other lights are also on. In this mode, push down the handle to change the high beam.

If you push and pull the handle up and down, you can give an overtaking signal.

Right handle. It is the wiper and windshield scrubber switch. There are four gears: OFF neutral, wipers do not work.

INT intermittent work (every 4 to 5s).

Lo works at low speeds.

Hi works at high speed.

If you pull the handle upwards, you can make the windshield washing liquid spray out. Some have a wash liquid button on the end of the handle.

Operate. In the middle of the upper part of the combination switch, there is a hazard warning flasher button, which can be turned on by pressing it down.

This kind of switch is mainly used to jog to the signal, and the specific action to be executed after pressing is determined by the internal single-chip microcomputer module program.

For example, if the power button of the mobile phone is x1, if the internal module program detects that the power supply is powered, and the screen or the relevant original of the mobile phone is not working in the standby state, it will be regarded as turning off.

If in this state, it is detected that X1 has a signal input to Huique, the time relay T1 in the module is energized and delayed, and then the power supply of each component required for booting is turned on, and the system starts. That's why when you turn on the phone, you have to press and hold the power button for a second before it turns on.

Just like when you flash your phone, you must press and hold the power button and the volume + button at the same time to enter the pink screen.

Assuming that the volume key is X2, that is, in the shutdown state, if the X1 and X2 signals are powered at the same time, then the program will enter the pink screen, otherwise the program will end, and the next sentence will be executed.