NC Proximity Switch
Most reed switches are filled with nitrogen at atmospheric pressure. After the final seal is made, the switch cools and the internal pressure is less than one atmosphere. Reed switches sealed with a pressurized nitrogen atmosphere have a higher breakdown voltage and are...
NC Proximity Switch
The voltage that does not change with time in both size and direction is called DC voltage.
In a DC circuit, the voltage applied across the power supply, at both ends of a circuit, and across the components is the DC voltage. For example, the voltage at both ends of the flashlight battery and the bulb is DC voltage. Due to the existence of series-parallel connection, the parallelism of electrical equipment increases (the shunt effect is parallel in resistance). The shunt current passes through the shunt branch. When the shunt current passes through the power load, it generates a “shunt voltage” (the shunt voltage is numerically equal to the product of the branch current and the shunt resistance). If the test voltage and current of the multimeter is the shunt function that uses the voltage divider in series with the resistor and the shunt resistor in parallel, the range can be changed. The voltage level chosen is extremely complicated. In fact, choosing a higher voltage will indeed save a lot of wires and energy. However, it will increase the cost of switching or electronic components, and it will not save much money. If we choose 100-120VAC when we start to develop electric power, we will reduce a lot of money in the direct use of the electric circuit of the rectifier circuit, and it will be even safer, and even the power line interference will be reduced a lot.
WHAT IS THE REED SWITCH CONTACT RESISTANCE?
Reed contact resistance (CR) is the DC resistance caused by the resistance of the gap between the dry reed itself (body resistance) and the switch terminals. Most of the contact resistance is found on nickel/iron dry reeds. Their electrical resistivities are 7.8x10-8Ω-m and 10.0x0-8Ω-m, respectively, compared to copper's resistivity (Cu's resistivity is 1.7. x10-8_Ω-m) This is quite high.
In general, the contact resistance of the entire reed switch is approximately 70 mΩ, and the resistance of the gap between the switch terminals is actually about 10 to 25 mΩ. On reed relays, the relay pins are usually made of nickel/iron to improve the overall magnetic performance, but this also increases the resistance of the reeds. The added resistance is about 25 to 50 mΩ.