隔離電流傳感器解決了電路的安全問題

　　在許多與電源有關(guān)的應(yīng)用中，必須知道導(dǎo)體中電流的多少。訣竅是了解許多電流可以測量的方式，并根據(jù)關(guān)鍵要求，如安全，功率，成本，形狀因子和電路可訪問性作出正確的選擇。

　　需要電流感應(yīng)的情況包括電機(jī)控制反饋，電源操作，或大功率充電太陽能電池陣列。當(dāng)電流與電壓低至中等，如在1和10 V，測量電流是相當(dāng)簡單：只需插入電流電阻（通常在毫歐的范圍）的電流進(jìn)行評(píng)估的路徑，然后測量電阻兩端的電壓。雖然有問題的大小的電阻器，以盡量減少不希望的電壓降，同時(shí)提供了足夠大的電位差（電壓）橫跨電阻的精確測量，這種關(guān)注可以解決一些基本的計(jì)算和一個(gè)合適的放大器橫跨電阻。

　　If the resistor is grounded at one end （called low-side sensing）， the measuring circuit is very straightforward. However， if the resistor is not grounded （high-side sensing）， a differential amplifier is needed to measure that voltage across the resistor – without any reference to ground. In many applications， the high-side sense circuit will also have to be galvanically isolated for safety or performance， usually using an optocoupler or transformer-based isolator.

　　Isolation of sensing circuitry is needed for technical and regulatory reasons in the many situations where high voltages and currents are common， such as line-operated industrial and commercial motors， electric/hybrid electric vehicles （EV/HEV）， solar arrays， home energy metering， and many other less-visible applications. It also adds a major safety barrier， often mandatory， in case there is a component failure or human failing which might put higher or primary-side voltages on the secondary-side circuit. It adds to cost and complexity， of course， but allows the sense resistor to be several thousand volts above ground.