How to protect electronic components from overvoltage? Yuhuaxin Electronics will introduce in detail here
Both industrial equipment and household appliances have a rated voltage. If the voltage exceeds this limit, it will exceed the insulation strength and withstand voltage of the appliance. As a result, the appliance will overheat, be damaged by breakdown, and even catch fire.
Especially in industrial production, voltage instability caused by equipment aging, technical failures, human errors, natural disasters, power outages and subsequent power reconnections all require the support of overvoltage protection devices.
The overvoltage protector is a protective mechanism that disconnects the power supply or controls the voltage of the equipment when the voltage exceeds the predetermined maximum allowable value. There are various types of overvoltage protectors that have emerged, some are installed inside the equipment, while others are installed at the power supply location. With this device, the equipment becomes safer like having an additional layer of insurance (RS Eurotime Electronics)
Common overvoltage protection components or devices include surge protectors, varistors, and lightning arrestors, etc.
RS Electronics Special Note: In the field of communication power supplies (such as 5G base stations), to prevent the sudden high voltage from lightning from causing significant damage to the equipment, voltage-sensitive resistors are usually configured to provide overvoltage lightning protection.
In complex industrial production safety, it is not just about dealing with lightning surge voltage. The principles of different overvoltage protection devices are all different. ETS Electronics believes that when making a choice, it is necessary to consider comprehensively based on the protection principle, working conditions, and usage environment.
Common overvoltage protection devices include: varistors, transient voltage suppressors, electrostatic suppressors and discharge tubes.
Today, RSonline Electronics will give you a brief introduction to the following: Voltage stabilizing diodes, transient suppressor diodes, Metal Oxide Varistors, and Gas Discharge Tubes.
Model 1: Voltage Stabilizing Diode
The voltage stabilizing diode, also known as the zener diode, is a semiconductor device that functions as a voltage stabilizer. It is made by taking advantage of the reverse breakdown state of the pn junction, where the current can vary greatly while the voltage remains relatively constant. This diode is a type of semiconductor device that has a very high resistance until the critical reverse breakdown voltage is reached. At this critical breakdown point, the reverse resistance drops to a very small value, and in this low-resistance region, the current increases while the voltage remains constant. Voltage stabilizing diodes are classified based on their breakdown voltage. Due to this characteristic, voltage stabilizing diodes are mainly used as voltage regulators or voltage reference components. Voltage stabilizing diodes can be connected in series for use at higher voltages, and by connecting them in series, a higher stable voltage can be obtained.
The voltage stabilizing diode brands provided by OSi Electronics include FagorElectronica, FairchildSemiconductor, Littelfuse, Magnatec, Nexperia, NXP, ONSemiconductor, Panasonic, TaiwanSemiconductor, etc.
Provided by RSonlie Oshi Electronics: ON Semiconductor single-channel 24V 5% 5W, 2-pin
RS inventory number: 654-7640. Manufacturer part number: 1N5359BRLG. Manufacturer: ON Semiconductor.
This voltage stabilizing diode belongs to the 1N5347 to 1N5363 series. This axial lead device has a molded package, with a non-porous transmission molded thermosetting plastic, providing protection under most common environmental conditions. The voltage regulator has strict limitations and better operational characteristics, reflecting the outstanding function of oxide silicon passivation cross-linking. The external surface is corrosion-resistant, and the wires are easy to solder.
Second item: Transient Voltage Suppression Diode
Transient Voltage Suppression Diode, abbreviated as TVS, is a high-performance protective device in the form of a diode. When the two terminals of the TVS diode are subjected to reverse transient high-energy impact, it can rapidly convert the high impedance between the two terminals to a low impedance at a rate of 10 to the power of -12 seconds, absorbing up to several kilowatts of surge power, and clamping the voltage between the two terminals to a predetermined value, effectively protecting the precision components in electronic circuits from damage caused by various electrical surge pulses.
Transient voltage suppressor diodes have the advantages of fast response time, high transient power, low leakage current, low breakdown voltage deviation, easy control of clamping voltage, no damage limit, and small size.
Transient voltage suppressor diodes are commonly used in:
Computer
Printer
Network system
ATM machine
Safety system
Wireless communication system
Medical equipment
The transient voltage suppression diodes provided by OSi Electronics include brands such as Bourns, Diodes Zetex, Fagor Electronica, Fairchild Semiconductor, HY Electronic Corp, Infineon, Littelfuse, Nexperia, ON Semiconductor, STMicroelectronics, and Taiwan Semiconductor.
Provided by RSonlie Eurotech Electronics: ON Semiconductor (Ameson) Schottky Diode 350W, 44V
RS inventory number: 102-2281
Manufacturer part number: NUP2105LT1G
Manufacturer ON Semiconductor
The ON Semiconductor NUP2105L/NUP3105L dual-line CAN bus protector can protect CAN transceivers in high-speed and fault-tolerant networks from ESD and other harmful transient events. The transient suppression diodes of RS will provide bidirectional protection for each data line, as they are packaged in a compact SOT-23 format, which helps ensure system reliability and meets strict EMI requirements.
Clause 3: Metal Oxide Varistors
The metal oxide varistor offers 7 mm and 10 mm pin-type varistor devices, which can prevent damage from instantaneous overvoltage, such as lightning, power contact, and power line induction. The metal oxide varistor can be selected for different voltages, ranging from 18 V to 820 V and from 11 V to 510 V of effective voltage. This device can handle high currents, absorb high energy, and react quickly to protect equipment from transient faults and stay within the rated limit.
Metal oxide varistors are usually composed of zinc oxide and are supplemented with small amounts of other metal oxides such as cobalt, manganese or bismuth. During the manufacturing process, these materials are sintered into ceramic casings.
Application of Metal Oxide Varistors:
Suppress lightning and other high-level instantaneous energies
Direct current circuit low-voltage power supply
Low-voltage power supply for automotive applications
Prevent internal transient phenomena during capacitor discharge, relay switching and inductor load switching
The brands of metal oxide varistors provided by RS Ohmite Electronics include AVX, BC Components, Bourns, EPCOS, Littelfuse, Panasonic, Roxburgh EMC, RS PRO, Vishay, and Wurth Elektronik.
Such as the Bourns metal oxide potentiometers provided by OSI Electronics RSonline
MOV-14D series, 430pF, 50A, 775V
RS inventory number 851-8335
Manufacturer part number: MOV-14D471K
Manufacturer Bourns
The Bourns MOV-14D series of 14 mm radial lead type varistor devices from Bourns offer protection against overvoltage transient phenomena such as lightning, power contacts, and power induction. The equipment features high current handling, high energy absorption capacity, and fast response time, which can prevent transient faults from reaching the rated limit and provide excellent reliability.
Article 4: Gas Discharge Tube
Gas discharge tubes refer to lightning arresters or antenna switch tubes used for overvoltage protection. These tubes have two or more electrodes and are filled with a certain amount of inert gas. Gas discharge tubes are gap-type lightning protection components that are used in the lightning protection of communication systems. They are commonly used in the first or first two stages of multi-level protection circuits, serving to discharge the instantaneous overcurrent of lightning and limit overvoltage. Due to the high insulation resistance between the electrodes and the small parasitic capacitance of the discharge tubes, they have obvious advantages in protecting against lightning for high-frequency signal lines.
The working principle of a gas discharge tube is that gas gap discharge occurs. When a certain voltage is applied between the two electrodes of the discharge tube, an uneven electric field is generated between the electrodes: under the action of this electric field, the gas inside the tube begins to ionize. When the externally applied voltage increases to the point where the field strength between the electrodes exceeds the insulation strength of the gas, the gap between the two electrodes will be discharged and break down, changing from an insulating state to a conductive state. After the discharge tube is turned on, the voltage between the two electrodes remains at the residual voltage level determined by the discharge arc path. This residual voltage is generally very low, thus protecting the electronic equipment connected in parallel with the discharge tube from overvoltage damage.
The gas discharge tube brands provided by RSonline by OSI Electronics include Bourns, EPCOS, Huber & Suhner, Littelfuse, TDK, etc.
For example, the EPCOS gas discharge tubes provided by OSI Electronics RSonline, the EHV series, 230V, 20kA
The maximum rated voltage is 230 V direct current, and it is mainly used in the main distribution frames of telecommunication exchanges and user-end equipment.
