II. Wiring Methods for Metal Button Switches
Metal keypad switches typically have two wiring methods: single-pole and double-pole. Single-pole wiring connects the switch to one circuit, while double-pole wiring connects the switch to two circuits. The characteristics and application scenarios of these two wiring methods will be introduced separately below.
Single-pole wiring
Single-pole wiring is the most common method for connecting metal push-button switches. In this configuration, the switch is connected to only one circuit. This wiring method is typically used to control the operation of a single device or circuit. For example, single-pole wiring can be employed to switch on or off devices such as lights, fans, and motors.
Wiring method:
Unipolar wiring refers to grounding one end of a metal button switch while connecting the other end to the positive or negative terminal of the circuit. This wiring method is commonly used in DC circuits, such as in small electronic devices powered by batteries. In a metal button switch with unipolar wiring, there are typically two pins: one connected to the metal casing of the switch and serves as the ground, while the other is connected to the positive or negative terminal of the circuit, functioning as the input or output. When the switch is pressed, the internal metal contacts either close or open the circuit, enabling control over the circuit's on/off state.
The advantage of single-pole wiring is its simple connection, making it suitable for basic circuit control. However, its drawback is that the contacts inside the switch may bounce when disconnecting the circuit, potentially causing brief interference signals in the circuit.
When connecting a single pole, the following points need to be noted:
Connect the power cord to the common terminal of the switch;
Connect the power cable and the device cable to the two terminals of the switch separately;
The polarity of the power cable should match the polarity required by the device;
Maintain good contact when wiring to avoid poor contact or excessive contact resistance.
Bipolar wiring
Bipolar wiring is another common method for connecting metal push-button switches. In this configuration, the switch connects to two circuits simultaneously, typically used to control multiple devices or circuits. For example, bipolar wiring can be employed to control the operation of devices such as fans and lights.
Wiring method:
Bipolar wiring refers to connecting the two terminals of a metal push-button switch to the positive and negative poles of a circuit, forming a complete circuit. This wiring method is commonly used in AC circuits, such as household appliances and lighting devices. In a metal push-button switch with bipolar wiring, there are typically four terminals: two are connected to the metal casing of the switch and serve as the ground, while the other two are connected to the positive and negative poles of the circuit, functioning as the input or output. When the switch is pressed, the internal metal contacts either close or open the circuit, thereby achieving control over the circuit's continuity.
The advantage of bipolar wiring is its better circuit stability, as the contacts do not bounce when disconnecting the circuit. However, its drawback is the relatively complex wiring process, requiring attention to the correct polarity connection of the switch pins to avoid errors such as reverse polarity.
When connecting with bipolar wiring, the following points should be noted:
Connect the power cord to the two terminals of the switch;
Connect the device cable to the two terminals of the switch;
The polarity of the power cord and equipment cable should match the polarity required by the device;
Maintain good contact during wiring to avoid poor connections or excessive contact resistance.Precautions for metal key switches
In addition to the correct wiring method, there are also some precautions to be taken to ensure the normal operation of the metal key switch. Here are a few aspects to pay attention to:
Control current and voltage
Metal key switches can withstand high currents and voltages, but still need to control the current and voltage according to the requirements of the equipment. Excessive current and voltage may damage the switch, thereby affecting the normal operation of the equipment.
contact pressure
Metal key switches require a certain level of contact pressure to ensure the quality of the switch's contact. If the contact pressure is too low, it may cause poor switch contact or excessive contact impedance, affecting the normal operation of the equipment. If the contact pressure is too high, it may damage the switch.
ambient temperature
Metal key switches need to operate within a certain temperature range, and high or low ambient temperatures may affect the performance and lifespan of the switch. Therefore, when using metal button switches, it is necessary to consider the impact of ambient temperature on the switch.
lifespan
The service life of metal key switches is an important indicator, usually used to evaluate the quality and performance of switches. The lifespan depends on multiple factors, including usage environment, current, and voltage. When choosing metal key switches, it is necessary to consider the service life and reliability requirements of the equipment.4、 Case analysis
Here are several application cases of metal key switches:
household appliances
Metal button switches are widely used in household appliances such as televisions, speakers, washing machines, etc. These household appliances require the control of multiple devices or functions, thus requiring the use of bipolar metal key switches. For example, a television needs to control volume, channels, etc., and requires the use of a bipolar switch.
Automotive Electronics
Metal button switches are also widely used in automotive electronics, such as car audio systems, air conditioning, electric windows, etc. Automotive electronic devices need to withstand harsh working environments and vibrations, so it is necessary to choose metal key switches with high lifespan and seismic performance.
industrial control
Metal key switches are also commonly used in industrial control, such as machine tool control, factory automation, etc. These applications require the use of metal key switches that can withstand high currents and voltages, and have good anti-interference capabilities to ensure the stability and reliability of the equipment.
medical equipment
Metal button switches are also widely used in medical equipment, such as surgical lights, monitors, etc. These devices require precise control and operation, therefore metal key switches with high precision and long lifespan need to be selected. In addition, as medical equipment usually requires disinfection and cleaning, it is necessary to choose durable switches that can withstand disinfection and cleaning.
other fields
In addition to the above-mentioned fields, metal key switches are also widely used in other fields, such as security equipment, military equipment, etc. These devices require high reliability and long lifespan, therefore high-quality metal key switches need to be selected.
The above are several application cases of metal key switches, each with different factors to consider. For example, in household appliances, factors such as voltage, current, lifespan, and operational sensitivity need to be considered, while in automotive electronics, factors such as waterproof, dustproof, and seismic resistance need to be taken into account. When choosing a metal button switch, various factors need to be considered comprehensively to select the switch that is suitable for a specific application scenario.
5. Conclusion
As a type of electronic switch, metal button switches have various advantages, such as durability, stability, and reliability. This article provides a detailed introduction to the wiring methods and precautions of metal key switches, and lists several typical application cases. When using metal key switches, it is necessary to select suitable switches according to the needs of the equipment, and pay attention to the correct wiring method and precautions to ensure the normal operation of the equipment.