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Bulk ceramic resistors vs film and wire-wound

Non-inductive bulk ceramic resistors are capable of handling extremes that film and wire wound resistors cannot. Ceramic technology offers the power range and non-inductive characteristics of film resistors but with overload and pulse energy capabilities that exceed the performance of wire-wound resistors – in a fraction of the footprint.

From soft-start and snubber circuits to dynamic braking and RF dummy loads, non-inductive bulk ceramic resistors have a wide range of applications, such as: radar, motor drives, broadcast transmitters, RF amplifiers, semiconductor process equipment, high voltage power supplies, switchgear, x-ray, lasers, medical defibrillators, and energy research. Electronic systems often require rugged resistors that perform reliably under conditions of high voltage, current, or energy.

Pulse, pre-charge and softstart

The compact pulse energy capability of ceramics allows flexible design without sacrificing power. Ceramic resistors can obtain greater power dissipation in one third of the footprint of wirewound resistors, delivering excellent performance where high peak power or high-energy pulses must be handled in small and efficient spaces.

Resistor technology comparison

Parameter Wire-wound Film Ceramic
Inductance (nH) 30-56000 2-200 2-200
Peak power Poor Poor Excellent
Overload Medium Poor Excellent
Pulsed energy Medium Poor Excellent
Geometry size Complex packaging Flexible Flexible
Power range 5 W to 1 kW 1 W to 1 kW 1 W to 1 kW

High Voltage

High voltage continuous and pulse applications can be addressed with ceramic resistors, including radar, x-ray, defibrillators, lasers, broadcast transmitters and semiconductor process equipment. These applications can include crowbars, capacitor charging or discharging, and high voltage power supply protection circuits. Bulk ceramic resistors can provide low inductance, high average power per unit size, stability at high voltage, and durability at extreme peak-power levels.

Snubber circuits

When a spike in voltage occurs from electrical switching, an RC snubber circuit is typically used to suppress the discharges and protect the circuit. However, a wire wound or film resistor may not hold up to the high voltage, current or energy conditions.  The power spike can result in megawatts of instantaneous peak power which a small mass of film or wire-wound resistors would potentially degrade and even fail.

High-frequency filters

Bulk ceramic resistors are used extensively for high-frequency loads in broadcast and communication equipment because of their non-inductive characteristics. They provide excellent non-inductive power-handling capacity at frequencies into the GHz range, with no sacrifice in power dissipation. In advanced digital applications such as digital radio and HDTV transmitters involving pulses at high frequencies, the small size, flexibility and overload reliability of ceramic resistors are ideal.

Test loads

High energy may be desired in a testing situation, from addressing minor circuit spike to the diversion a lightning strike. In the case of power generators, test loads allow for a low-risk verification of a unit’s capabilities.

Useful Documents

Kanthal tubular resistors datasheet

Tubular Resistors Datasheet

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Axial-leaded Resistors Datasheet

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AS Series Slab Resistors Datasheet

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SP Series Slab Resistors Datasheet

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Series 900 Disk and Washer Resistors

 

 

 

 

 

Useful Links

Resistors

Ceramic resistors

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