Pre-Charge Resistors | Thin Film Resistor Manufacturer | FIRSTOHM

Pre-charge circuit is a circuit design principle where specific components (such as capacitors) are pre-charged before the electronic device is powered on and then connected to the main circuit. The purpose of this is to reduce the current impact during startup, protecting the system and components from excessive voltage or current effects. This pre-charge principle effectively reduces the impact during the startup of electronic devices, prolongs the lifespan of system components, and enhances the overall stability of the system. FIRSTOHM is a high performance MELF resistors, SMD resistors, metal film resistors, surge resistors, wire wound resistors, precision resistors, High voltage resistors, high Power resistors, metal oxide resistor, thin film resistors, fixed resistors manufacturer from Taiwan since 1969. FIRSTOHM is one of the few companies who is able to design thin-film MELF resistors according to customer's requirements with high quality and reliability. We’re specialized in thin-film resistors since 1969, ISO9001/14001 certificated manufacturer. Over 55 years of industry experience for resistors design and manufacturing facility.

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Pre Charge Resistor | Automotive-Grade Resistors Manufacturer | FIRSTOHM

FIRSTOHM 's products are suitable for Pre-Charge application. | More than 55 years of resistor manufacture experience

FIRSTOHM 's products are suitable for Pre-Charge application.

Pre-Charge Resistors

Pre Charge Resistor

Pre-charge circuit is a circuit design principle where specific components (such as capacitors) are pre-charged before the electronic device is powered on and then connected to the main circuit. The purpose of this is to reduce the current impact during startup, protecting the system and components from excessive voltage or current effects.
This pre-charge principle effectively reduces the impact during the startup of electronic devices, prolongs the lifespan of system components, and enhances the overall stability of the system.


Welding point patents of FIRSTOHM Wire Wound MELF Resistors:

1. Taiwan patent number: M530462

2. Japan patent number: 3208923

3. China patent number: ZL201490001291.X

4. Korean patent number: 20-0486309

5. United States patent number: US9978483B2

Application
  • Industrial Power Supplies
  • Inverters
  • Battery Management Systems
  • Electric Vehicle Charging Stations
  • Energy Storage Systems
  • Industrial Equipment
General Specification

FIRSTOHM Anti-Surge Wire Wound Resistors (SWM/SWA): Possessing multiple-country welding point patents, these resistors enhance product reliability, offer high pulse withstand capability, are cost-effective, and come in a compact size. They are particularly suitable for use in pre-charge resistors or discharge resistors.

※ Type of pre-charge resistor

※Reference Case: Pre-charge Circuit for Inverters

FIRSTOHM P/N : SWA03J68R0TKZTB500(3W 68R 5%) *1PCS

Test Conditions: Input Voltage: 357.8VDC,Charge Capacitance: 648μF,Number of Test Cycles: 10,000 cycles

Test Result: △R:+0.42% (PASS)

Maximum Power = 357.8V x 357.8V/68R = 1882W, Time Constant (RC/2) = 22ms (In pre-charge applications, the time constant when energy is at its maximum depends on the values of the RC (resistor and capacitor) components in the circuit. The time constant (τ) is typically calculated as half of the product of RC. Time Constant (τ) = RC / 2.")

SWA03 can withstand 3,000W under 22ms. (refer to the SWA03 surge performance chart below.)

※ Firstohm-The specifications of Anti-Surge Wire Wound MELF Resistors (SMD) are as follows:

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Anti-Surge Wirewound MELF Resistor
Anti-Surge Wirewound MELF Resistor

Anti-Surge Wirewound MELF Resistor can operate in high ambient temperature with less resistance drift.

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Anti-Surge Wirewound Resistor
Anti-Surge Wirewound Resistor

Anti-Surge Wirewound Resistor is operating in the high ambient temperature where amti-surge and power dissipation are required.

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Pre-Charge Resistors | Surge Resistant MELF Resistor Manufacturer | FIRSTOHM

Located in Taiwan since 1969, First resistor & condenser Co. Ltd. has been a manufacturer of MELF resistors manufacturer. Their main thin film MELF resistors include, automotive grade resistors, surface mount resistors, fusible resistors, SMD resistors, chip resistors, fixed resistors and fusible thin film resistors, which are being widely used in industrial applications such as power supply, smart meter, solar inverter, energy storage device, electric vehicle, communication equipment, and medical device.

FIRSTOHM is one of the few companies who is able to design thin-film MELF resistors according to customer's requirements with high quality and reliability. We’re specialized in thin-film resistors since 1969, ISO9001/14001 certificated manufacturer.

FIRSTOHM has been providing customers with high quality carbon film and metal film resistors since 1969, with both advanced technology and 55 years of experience, FIRSTOHM ensures that each customer's demands are met.