Do now: An AC generator produces a peak voltage of 6V. It is connected to a heater which has 30Ω resistance. a)Calculate the peak current and RMS current b)Calculate the RMS power c)What DC voltage would the heater need to work just as well as on the AC voltage? Paraire, 16 Whiringa-ā-nuku 2015

In pairs, discuss: What happens to the bulb in the AC circuit compared to the DC circuit? ~

In a DC circuit, the current flows until the cap is fully charged and then stops. In an AC circuit, the current can continue to flow, as the plates become alternately charged positively and negatively ~

Reactance For both AC and DC circuits, the voltage across the resistor is related to the current by V=IR A similar relationship exists for a capacitor: Where X c is the reactance of the capacitor ~

Reactance Reactance is a measure of how a capacitor can limit alternating current Unit: Ohms It is similar to resistance but differs in that it is dependent on the frequency of the ac supply. It also depends on the size of the capacitor.

Reactance Explanations: Higher f means cap never gets full before current direction changes, so never limits current, so low X Higher C means that it takes more charge to fill it, so never fills before current direction changes, so never limits current, so low X