Contents
What is the power of a resistor?
The power rating of a resistor indicates how much power a resistor can handle before it becomes too hot and burns up. Power is measured in units called watts. The more watts a resistor can handle, the larger and more expensive the resistor is. Most resistors are designed to handle 1/8 W or 1/4 W.
What is meant by surge current?
Surge currents are the “currents that raise or fall from the normal rated value in the short duration of time”. These are the instantaneous sharp impulse currents. Surge currents occur due to the lightning strikes. Surge currents occur in the electrical machines during their turn on conditions.
What is resistor and its function?
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
How do you calculate surge current?
Well, to calculate the Surge Current you must know the current density of the bolt of lightning. You will have to have to move at the speed of light to measure the width of the arc, but you will burst into flame any due to the air resistance as you accelerate up to the speed of light.
Why are pulse withstanding resistors used in power electronics?
These variations result in a corresponding variability in the pulse handling capability of these resistors and make using standard thick-film chip resistors for pulse handling situations problematic. Pulse withstanding chip resistors are designed to maximize the usable width of the resistive element.
What are the TCRs of a pulse resistor?
Chip resistors with this kind of resistive element can achieve resistance values up to 50 Gigohms, and can maintain precise tolerances down to 0.5% and TCRs as low as 25 ppm. This level of precision is rarely seen in a thick-film chip resistor, and certainly not from a high-voltage chip resistor.
How many pulses can a riedon wire wound resistor handle?
For long pulses up to of 5 seconds, Riedon’s wire wound resistors are designed to meet the industry-standard specification of 5 times rated power for 5 seconds. This applies to all values and all resistances. For example, a 5W resistor can handle 25W for 5 seconds (125 Joules) regardless of package size or resistance value.
Can a wirewound withstand a high power pulse?
Wirewounds can be built to withstand very high power pulses for short durations with extremely little resistance shift; and in some cases can also withstand relatively high energy ( Fig. 1 ).