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Thick Film Resistor In Radar Applications

RADAR systems may be complex but their operation relies on a range of relatively simple resistor components. Resistors are used in pulse forming, sensing, switching, current limiting and RF termination applications, among others.

In the late 1800’s Heinrick Hertz proved that radio waves travel in a straight line and are reflected by a metal object. In RADAR equipment a pulse of high frequency radiation is emitted, based on the time and direction of the returning pulse the distance and direction of a metallic object may be calculated.

High Power Resistor Design and Manufacture

To deliver a high power resistor that continues to operate with minimal performance degradation over its in service life requires both a detailed knowledge of potential failure modes and thick film resistor manufacturing techniques.

Typical causes of high power resistor failure include:
Thermal stresses.
Surge & ESD.
Mechanical stresses and environmental factors.

HEAT MANAGEMENT

The Resistor Network Manufacturing Process

Resistor networks are found in many applications including resistor divider (precision amplifier) circuits, measurement systems, test equipment and industrial automation. The most common application is relatively simple pull up / pull down resistor arrays but for more complex circuits including matched resistors or specialist, application specific, devices a high degree of resistor network manufacturing and design expertise is required.

Thick Film Resistors Vs Thin Film – A Comparison

What are the advantages of thick film resistors over their thin film cousins? In this post we consider the ideal resistor and discuss how both thin film and thick film resistors compare with that ideal.

The Ideal Resistor

The perfect resistor has zero capacitance and inductance. Its resistance value is precisely known and does not vary over its entire in service life regardless of any external environmental factors such as moisture or temperature..

Thick Film Resistor Design Considerations

When designing any electronic system there are compromises to be made in component selection. This extends to what may be perceived as the simplest components including resistors and capacitors. In this post we consider typical thick film resistor design and application issues the system designer needs to consider.

The Perfect Resistor

Power Resistors In Current Sensing Applications

Power resistors are used in a variety of power electronic applications as load resistors, braking resistors and pulse management devices but one of the main applications is current sensing elements in power supplies and electric motor control.

When designing power supplies one of the key design challenges is minimising overcurrent and short circuit conditions that may damage sensitive electronic components used in the motor control circuitry. These overcurrent conditions can be caused by a number of factors including motor start-up conditions and high power switching.

High Voltage Resistor Manufacturing And Its Impact On Performance

High voltage resistor devices are available to a wide range of quality standards. It is important for the designer to understand the trade-off between cost and reliability of the resistor device and to fully understand the application if resistor failure is to be avoided.

Replacing An Obsolete Resistor

Electronic component obsolescence has been a major issue for high reliability equipment manufacturers (and increasingly standard equipment manufacturers) for many years. Although many manufacturers now have robust obsolescence management processes in place the rate of obsolescence is increasing and it can be difficult to keep pace.

How To Select The Best Resistor Technology For Specialist Applications

When choosing the best resistor technology for a specialist application it is important to go further than a simple review of datasheet parameters. The datasheets covering several different resistor constructions may appear to be similar but it is important to understand the advantages and disadvantages of each resistor manufacturing method.

Thick Film Power Resistor Failure Modes

Thick film power resistor failure is often related to environmental or transient conditions that were not considered during the component design phase. Mechanical stresses, thermal issues, constant overload or surge conditions and mounting issues can all degrade the power resistor device or, in some cases, cause catastrophic failure. Handling issues, including ESD, can also have a major impact on the reliable operation of the resistor device.

MECHANICAL FAILURES

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