The adjustable resistor stands for the pass element of a linear regulator. If we were to select a positive linear regulator that can source and sink currents, there The problem with using a typical linear regulator that is intended for positive output voltages is that it can only source current and not sink current. Can such a positive linear regulator be used in applications where negative voltages need to be converted?įigure 1 shows a linear regulator used in such an application. There is a very large selection of linear regulators available on the market suited for positive voltages. For accurate –3.3 V generation, we want to use a linear regulator. Typically, such voltages are not regulated very accurately. This voltage rail may come from a transformer-based power supply. For the necessary negative voltage of –3.3 V, an available support voltage of –5 V may be utilized. These signals may be between +2.5 V and –2.5 V. For sensing these signals, we are using an operational amplifier that requires a positive supply voltage of +3.3 V and a negative supply voltage of –3.3 V.įor the positive voltages, +3.3 V are already available in the system. In such a system, the signals of a sensor shall be measured and recorded.
Figure 1 shows an example with a supply voltage of 3.3 V and a system ground potential of 0 V.
In such a case, one would not choose the description “negative voltage.” By negative voltage, we mean that one voltage is lower than a system’s ground potential. This means that one voltage can be higher than another voltage. Between different electrical conductors, there can be different electric potentials. What are negative voltages? With voltages, everything is relative.
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