Wired this way, see the following diagram:
As long as the above conditions are met, whether it is four or more switches are so connected.The word switch is explained as on and off. It also refers to an electronic component that opens a circuit, interrupts the flow of electricity or allows it to flow to other circuits. The most common type of switch is a human-operated electromechanical device that has one or more electronic contacts. The "closed" (closed) contact means that the electronic contact is open, allowing current to flow through; the "open" (open) switch means that the electronic contact does not conduct to form an open circuit, not allowing current to flow through.
Basic Classification
By Application
Wave switch, wave switch, record and playback switch, power switch, preselector switch, limit switch, control switch, changeover switch, isolation switch, travel switch, wall switch, intelligent fire switch and so on.
By structure
Micro switches, boat switches, knob switches, toggle switches, pushbutton switches, key switches, membrane switches, intelligent fireproof switches, safer steel frame switches and so on.
By the number of switches
Single control switch
Double control switch
Multi control switch
Dimmer switch
Speed switch
Splash-proof box
Doorbell switch
Sensor switch
Touch switch
Remote control switch
Smart Switch
Plug-in power switch
Switch for bathtub
Network switch
Basic structure
The simplest switch has two pieces of metal called "contacts", which form a circuit for the electric current when they are in contact with each other, and open the electric current when they are not in contact with each other. When choosing a contact metal, it is important to consider how well it resists corrosion, as most metals oxidize to form an insulating oxide that prevents the contact from functioning properly. Selection of contact metal also need to consider its conductivity, hardness, mechanical strength, cost and whether toxic and other factors.
Sometimes on the contact plating corrosion-resistant metal. Typically plated on the contact surface of the contact to avoid oxides that can affect its performance. Sometimes non-metallic conductive materials, such as conductive plastic, are used on the contact surfaces.
In addition to the contacts in the switch, there will also be movable parts to make the contacts conductive or non-conductive, the switch can be divided into lever switch (Toggle switch), key switch, boat switch (Rocker switch), etc., and the movable parts can also be other types of mechanical linkage.
Time-delay switch
Time-delay switch is the use of electronic components relay installed in the switch, delay switch circuit of a switch. Time delay switch is also divided into voice-activated time delay switch, light-activated time delay switch, touch time delay switch and so on. The principle of the time delay switch is the principle of electromagnetic relay, the working principle of the relay is that when the relay coil is energized, the iron core in the coil produces a strong electromagnetic force, sucking the armature to drive the reed, so that the contacts 1, 2 disconnected, 1, 3 connected. When the coil is de-energized, the spring resets the reed, making contacts 1 and 2 on and 1 and 3 off. We can use the relay to achieve some kind of control by simply connecting the circuit to be controlled between contacts 1 and 2 (1 and 2 are called normally closed contacts) or between contacts 1 and 3 (called normally open contacts).
Principle of operation
The power switch K2 will be closed, and then press the button switch K1, this time, the crystal diode V1, V2 conduction, the relay suction. At the same time the power supply charges the capacitor C. When K1 is disconnected because C has been charged, it will be discharged through R and V1V2, thus maintaining the transistor continues to conduct, the relay is still engaged. After a period of discharge, the voltage between the poles of C falls to a certain value, not enough to maintain the triode continues to conduct, the relay is released. The time interval from K1 disconnection to relay release is called the delay time. It is determined by the size of R and C. Generally, when C is 100 microfarads, the adjustable resistor R can be adjusted to obtain a delay time of 10 seconds to 90 seconds. If C takes 1000 microfarads, the delay time can be more than 5 minutes.
The diode connected in parallel on the relay plays a protective role to prevent the relay from damaging the crystal transistor due to the high voltage generated by self-inductance when the relay is released from power failure.
Printed circuit board and component specifications
The printed circuit board of the time-delay switch circuit is shown in Figure 3-26 (A). A physical drawing is shown in Figure 3-26 (B).
Component specifications:
J Relay 4098 type operating voltage 6V V1V2 crystal transistor 9014 VD crystal diode 2CP10 or 1N4001 R adjustable resistor 100k C electrolytic capacitor 100u/6V K1 push button switch.
Tact switch
Tact switch tact switch, use gently press the switch button can make the switch on, when the release of the hand switch that is disconnected, its internal structure is to rely on the metal shrapnel by the force of the elasticity of the flick to realize the on and off. The internal structure of the switch relies on the force of the metal shrapnel to realize the on/off switch, such as the IKI series of light-contact switches.
Touch switches are widely used in electrical appliances due to their small size and light weight, such as: audio-visual products, digital products, remote controls, communication products, and so on. Digital products, remote control, communication products, household appliances, security products, toys, computer products, medical equipment, automobile buttons and so on.
Dual-control switch it is generally used in the stairs or walkway at both ends of the two different places, can each independently control the same light on or off. As shown in the figure provides three different connections, S1, S2 are 1 × 2 single-pole double-throw switch, they can each independently control the light E light or off. Figure (b) connection, because each switch within the simultaneous existence of the power supply phase and zero line, so the installation is more convenient, but the maintenance of special attention to be careful to prevent the phase, zero line short circuit at both ends.