Reading component reference designators
Contributed by
CircuitScope · Added 05 Oct 2026 · 2 views
What U, R, C, Q, D and the rest mean when you're tracing a fault.
Reference designators tell you what each part is at a glance:
- U / IC — integrated circuit (chip)
- R — resistor · C — capacitor · L — inductor / coil
- Q — transistor · D — diode (incl. LEDs, often LED)
- F — fuse · FB — ferrite bead
- J / CN / P — connector or header
- SW — switch/button · Y / X — crystal / oscillator
- TP — test point