Sensors — circuits that feel the world
Resistors that change their value based on what's happening around them.
Read first: Resistance
A sensor is a special kind of part whose resistance changes based on something in the world — light, heat, sound, motion. By plugging one into your circuit, the circuit can react to what's happening.
Four common sensors
· LDR (light) — high resistance in the dark, low in the light. Used in night-lights and street lamps.
· Thermistor (heat) — resistance changes with temperature. Used in thermostats and ovens.
· Microphone (sound) — turns vibrations in the air into a tiny electrical signal. Inside every phone and laptop.
· Accelerometer (motion) — knows when something tilts or shakes. The reason your phone can tell when you flip it sideways.
Now you understand…
- Sensors change resistance based on what's happening.
- Common kinds: light (LDR), heat, sound, motion.
- A sensor lets a circuit react instead of just sitting there.
Sensors give input. Now meet the part that makes decisions about it.