Current sensing involves converting electric current into an observable form. Current sensors and resistors can measure current flow, while pickup coils and clamp meters use magnetic induction. Current sense amplifiers are used in electronics and power management systems to detect faults in circuits.
Current sensing is the sensing and conversion of electric current into an observable form. Electric current is the rate of flow of electric charges. The higher the current in a fixed resistor, the higher the voltage across that resistor. Current flow can be measured using current sensors, while current sense resistors convert current to voltage.
A resistor is a partially conductive material that limits current, like a faucet that controls the rate of water flow. When electrical voltage has no associated current flow, it is similar to a closed faucet shutting off a high pressure water source. An equivalent current sensing device is a flowmeter, which uses a rotating vane that spins faster when the flow rate is high. The speed of the blade is proportional to the flow rate.
Another way of current sensing is the use of pickup coils magnetically coupled to a current source from a magnetic core. This is compared to the transformer principle, where a current on the primary winding of a transformer is induced in the secondary winding. The stronger the primary current, the higher the secondary current.
The clamp on current meters works on the principle of magnetic induction. When the magnetic core is clamped around a current-carrying wire, a secondary current is induced, which is a function of the primary current. Handheld clamp meters usually have voltmeters on the same device. The ability to measure current without breaking the test circuit as well as measure voltage make this test equipment very useful in preventive and corrective maintenance.
Power management systems use current sensing to detect faults in the circuit. If three-phase lines are to have a balanced load, for example, the neutral wire will normally have zeroed current through them. The sensing of the neutral wire current is a basis for a faulty condition and through this an adequate response is obtained.
Current sense amplifiers have many uses in electronics, automation, and instrumentation. The current sense resistor is usually a part of and in series with the bus bar that supplies power from the battery side of the rectifier to the load side. Voltage sense amplifiers can sense a sample proportional to the current flowing. If there is a current of 100 amperes (A) through a resistance that is 0.001 ohm, the voltage seen is 0.1 V corresponding to the load current of 100 A. The mentioned resistor together with the voltage sense amplifier is configured as an amplifier current sensing.
Protect your devices with Threat Protection by NordVPN
