Comparison of Active and Passive Isolators

An active isolator circuit comprises a power-supply section, an input section, and an output section. The input signal is processed by the input circuit to convert it into a specific digital signal or electromagnetic wave, which is then isolated electrically via an isolation component. The isolated digital signal or electromagnetic wave is subsequently converted back into an analog signal by the output circuit. The operating power for the active isolator is supplied independently; the circuit converts the input power into multiple voltage rails to provide the necessary operating energy for both the input and output circuits. An active isolator can isolate various types of input signals, including voltage, current, and frequency, and the signal amplitude can be freely selected—as long as the input circuit can handle the signal, it can be fed in and isolated.

Nanjing Paroken Technology Co., Ltd. separation Disconnector Products include: Active isolator and Passive Isolator Many customers have numerous questions regarding product selection; therefore, the following explanation is provided for these two products.
Active isolator The circuit comprises a power supply section, an input section, and an output section. The signal is processed by the input circuit to be converted into a specific digital value or electromagnetic wave, after which isolation components are used to achieve electrical isolation. The isolated digital value or electromagnetic wave is then transformed into an analog signal by the output circuit. In an active isolator, the operating power is supplied independently; the circuit converts the input power into multiple voltage rails to provide the necessary operating energy for both the input and output circuits. Active isolators can isolate various types of input signals, including voltage, current, and frequency, and the signal amplitude can be freely selected—as long as the input circuit can handle the signal, it can be fed in and isolated.
Active isolator The output circuit can generate a variety of signals, such as 0–10 V and 4–20 mA (PA-1187), which are proportional to the input signal—though the relationship is not necessarily a strict 1:1 match. In other words, it performs signal conversion. For current-input active isolators, the input impedance is only 50 Ω, making them easy to drive with most current sources. For current-output active isolators, the load capacity is relatively high, and variations in the load do not affect isolation accuracy.
Passive Isolator The circuit comprises an input section and an output section. The signal is first processed by the input circuit to be converted into an electromagnetic wave, which then passes through an isolation component to achieve electrical isolation. The isolated electromagnetic wave is subsequently transformed back into an analog signal by the output circuit. The operating power for this passive isolator is derived from the input signal terminal; therefore, the input signal must have sufficient drive capability to operate the device, and a certain voltage drop (approximately 4 V) will occur. This passive isolator can isolate DC current signals in the range of 0–20 mA, with a one-to-one correspondence between the input and output. The ideal load impedance for the passive isolator is below 300 Ω, though it can accommodate up to 500 Ω. Moreover, the passive isolator exhibits very low power consumption—less than 100 mW—making it an environmentally friendly and energy-efficient product.