Column: Optical isolation


sections are powered by isolated +12V power supplies, and we use two separate LM358P op-amps and an HCNR201 optocoupler. We assume VIN 5.00V. When 0.00V ≤ VIN output voltage VOUT


to be 0.00- ≤ 5.00, the = VIN


Calibrating PUPIA Set the input voltage VIN


; see Figure 6. to +5.00V and,


then, by adjusting P1, make sure the output voltage VOUT


= +5.00V. Te positive unipolar photovoltaic Figure 2: VOUT vs VIN in PUPIA1 design


isolation amplifiers explained here play a very important role in the isolation of analogue input and output modules, which will be discussed in future articles.


Continues on next page >


Figure 3: PUPIA2 design


Figure 4: VOUT


vs. VIN


in PUPIA2 design


www.electronicsworld.co.uk February 2022 17


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