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Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

DC

Direct current: current that flows in one direction at a steady voltage, as from a battery.

Direct current flows one way only. Every circuit in this course runs on low-voltage DC from USB, batteries or bench supplies.

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