Tuesday, March 19, 2024

Materials

U.S. Resistor utilizes 2 different base materials to manufacture our Ceramic Resistor Disc / Washer and Rod / Tubes.

Our original material has Zirconium Silicate as the base material and has the prefix of 83-xxxx to designate for this material.

We now offer Alumina as a base material and has the prefix of 85-xxxx to designate for this material. The Alumina offers a lighter weight material which can be significant on many applications but offers the same electrical characteristics as the original Zirconium Silicate material.

Ceramic resistors are manufactured from a sintered body of ceramic material, with conductive particles distributed throughout the matrix, to produce a resistor that is 100% active and non-inductive. Ceramic resistors are chemically inert. They can withstand high-energy and high-voltages at high temperatures, such as those encountered in the protection of high voltage surge equipment, discharge banks, and in high frequency radiation suppression.

Resistivity Range 83 – Zirconium Base 0.8 to 4,000 Ohm-in
2 to 10,000 Ohm-cm
85 – Alumina Base 2 to 4,000 Ohm-in
5 to 10,000 Ohm-cm
Maximum Steady State Power Density  
12 watts/in³
0.75 watts/cm³
Maximum Transient Energy Density   4,920 joules/in³
300 joules/cm³
Maximum Voltage Gradient
 
10 kV/in
  4 kV/cm
Maximum Rate of Power Injection
 
150,000 watts/sec/in³
Maximum Rate of Current Injection
 
1,000 amps/in² - Contact Area
Maximum Operating Temperature
 
250° C
Voltage Coefficient
 
- 0.3% to - 7.5% /kv/cm
Temperature Coefficient
 
- 0.03% to - 0.16%/°C
Heat Dissipation
 
2.86 watts/in²
Thermal Conductivity
 
0.03 cal / cm. sec 0C
Specific Heat
 
0.2 cal/gm/°C
Coefficient of Thermal Expansion
 
4 x 10-6
Heat Capacity
 
8.7 cal/°C/in³
Density (Nominal)  83 – Zirconium Base 2.55 g/cc
 85 – Alumina Base 2.30 g/cc