polarity converter

polarity converter very Analogue or digital voltmeters (or both!) are a important requirement for the electronics labora- tory, be it amateur or professional. Therefore, the easier it is to measure voltages, the better. In the case of most analogue meters and some digital ones, it can be something of a nuisance when the probes have to be changed round every time the voltage to be measured assumes the opposite polarity to the one measured previously. Forgetting to do this could result in rather disastrous consequences!! The circuit presented here helps matters consider- ably, as the output voltage will always be positive irrespective of the polarity of the input voltage. The circuit also has a "polarity" output which will hen the input voltage is produce an output of + B positive and —UB when the voltage to be measured is negative. Provided the circuit is calibrated cor- to the rectly, the overall accuracy is guaranteed voltage better than 0.5% of the maximum input (TUh)e).calibr...