Reference sheet
Vf per colour, so the series resistor comes out right
Typical range at rated current — use with the LED series resistor calculator. Always check the specific LED's datasheet for precise values.
| Color | Typical Vf |
|---|---|
| Infrared | 1.2 – 1.6 V |
| Red | 1.8 – 2.2 V |
| Orange / Yellow | 2.0 – 2.2 V |
| Green (standard) | 2.0 – 3.5 V |
| Blue | 2.8 – 3.6 V |
| White | 2.8 – 3.6 V |
| UV | 3.0 – 3.5 V |
Capacitor codes104 = 100 nF — decode the three-digit marking and its tolerance letter
Capacitor ESR & rippleWhat ESR costs you, family by family
Capacitor typesX7R vs C0G vs electrolytic — which dielectric for which job
Common diodes1N4001, 1N4148, Schottky and zeners with their real limits
Crystal load capacitorsSize C1 and C2 from the crystal's CL, and why it matters
E12/E24 valuesThe resistor values that actually exist, and their tolerances
MOSFET comparisonWhich jellybean part actually switches fully at 3.3V or 5V
Op-amp comparisonLM358, TL072, MCP6002 and co: supply, offset, speed