Chapter 4. Voltage and Current Changes and Time Constants

Voltage and Current Changes Through Resistors

If current through a resistor changes, voltage across the resistor changes immediately. There are no time lags for voltage or for current through resistors. Therefore, the impedance that a resistor offers to the flow of current is solely a function of the size of the resistor. Frequency does not play a role. This is one of the biggest distinctions between resistors and the other two types of components.

If we plot the relationship for either voltage or current for a resistor over time, it is a straight line. For example, Figure 4-1 plots current through time for a fixed voltage applied across three different resistors. I do that here simply as ...

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