Reading wiring diagrams — the electrician’s language

A schematic shows connections as symbols: zigzag = resistor, triangle with arrows = LED, circle with M = motor. Golden rule: common GND! All parts share the same "ground" — otherwise signals don’t understand each other. Never mix 5V and 3.3V: a 3.3V sensor burns on 5V (the ESP32 is a 3.3V board). A schematic reads left to right: supply → load → ground. Same principle as our lab: from the red rail to the blue one through all parts.

• ●Pull-up/pull-down defines the pin’s "silence" — without it the input picks up noise
• ●A €15 multimeter is the main tool: the beeper mode checks connections
• ●Our <a href="/elektro/labor" class="underline">Circuit Lab</a> follows the same laws: gaps, polarity, resistors