Non-earthed voltage supply for polarograph probe operation - is collected from insulated source in series with polarographic cell between inputs of differential amplifier

摘要

The polarograph is supplied with a non-earther operational voltage. The supply voltage, collected from an insulated source, is in series with a polarographic cell (1) between the two input terminals (20, 21) of a differential amplifier (2). Its inverting input is connected to a negative feedback circuit (22), and amplifier (2) output voltage is collected between its non-inverting input (21) and output, and applied to an isolating amplifier (4). The non-inverting input (21) is connected to the tap (35) of a voltage divider (33-34) which reduces the supply voltage (3) to the polarograph voltage of about 700mV.