Power Budget per Reading across Competing Sensing Principles
Sensing power budgets depend on physical excitation energy, analog settling delays, and converter sampling overhead across operating duty cycles.
Pulse Current Transients
Electrical Surge
Sudden changes in the flow of electricity can exceed the steady state capacity of a circuit for a very brief duration. Pulse current transients occur during the switching of inductive loads, lightning strikes, or the startup of high power motors. These events are characterized by a rapid rise time and a high peak magnitude compared to the average operational current.
Component Stress
Semiconductors and resistors must absorb the energy of the surge without reaching destructive temperatures. When pulse current transients hit a shunt resistor, the local heating happens too fast for the heatsink to dissipate the energy. This results in an instantaneous temperature spike that can shift the resistance value or melt the internal junctions.
Measurement Interference
Capturing these events requires high bandwidth instrumentation and fast sampling rates. Standard digital meters often miss pulse current transients because the integration window is longer than the pulse itself. Specialised peak detection circuits are needed to record the maximum value and the total energy of the event.
If the protection circuitry is too slow, the transient can pass through to sensitive logic components and cause hardware failure.
Suppression Method
Protection involves the use of transient voltage suppressors or metal oxide varistors. These devices divert the pulse current transients to ground once a threshold is crossed.