Two types of potential difference
Two types of potential difference

A direct potential difference, or dc, acts in one direction only. A cell or battery supplies direct potential difference because its terminals keep the same polarity: one remains positive and the other remains negative.
Step-by-step lessons on AQA GCSE Physics 2.3.1 Direct and alternating potential difference. Each one builds up to exam-style questions. Build a strong grip on equations, units and Key Stage 3 fundamentals before tackling the more demanding topics like electromagnetism, the particle model of matter and space physics.