T5A Current and voltage: terminology and units, conductors and insulators, alternating and direct current

Part of subelement T5 — ELECTRICAL PRINCIPLES, which contributes 4 questions to every exam across 4 groups.

Lessons covering this

Alternating Current7 min
Say what makes a current alternating, why radio requires it, and what a cycle and a hertz actually count.
Reading a Waveform: Peak, Peak-to-Peak, and RMS9 min
Convert between the three voltages a single AC waveform has, and know why a scope and a multimeter disagree about the same signal.
Charge, Current, and Voltage8 min
Name the three quantities every circuit is described with, say which units they use, and explain why voltage is always measured between two points.
Power, and Why Things Get Hot9 min
Compute power from any two of voltage, current, and resistance, and use the I-squared form to predict where a station will overheat.

T5A01 · T5A02 · T5A03 · T5A04 · T5A05 · T5A06 · T5A07 · T5A08 · T5A09 · T5A10 · T5A11