Quick Reference
The values, codes, and conventions used throughout the site, pulled into one page for fast lookup. Each table links back to the chapter that explains the why behind the numbers.
Unit Prefixes
Capacitors climb pF → nF → µF; resistors climb Ω → kΩ → MΩ. Each step is ×1,000.
| Prefix | Multiplier | Used for |
|---|---|---|
| p (pico) | ×10⁻¹² | Capacitors (pF) |
| n (nano) | ×10⁻⁹ | Capacitors (nF) |
| µ (micro) | ×10⁻⁶ | Capacitors (µF) |
| — (base) | ×1 | Ohms (Ω), Farads |
| k (kilo) | ×1,000 | Resistors (kΩ) |
| M (mega) | ×1,000,000 | Resistors (MΩ) |
Full chapter: Ohm's Law and Basic Circuit Theory →
Resistor Color Code
Standard 4-band code, read left to right: 1st digit, 2nd digit, multiplier, tolerance.
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Grey | 8 | ×100,000,000 | — |
| White | 9 | ×1,000,000,000 | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
| No band | — | — | ±20% |
Example: brown-black-red reads 1, 0, ×100 → 1,000Ω (1kΩ).
Full chapter: Resistors and Capacitors →
Capacitor Types
| Type | Typical range | Where you'll find it |
|---|---|---|
| Ceramic | picofarads to low nanofarads | High-frequency filtering, tone-shaping networks |
| Film (polyester/mylar) | nanofarads to low microfarads | Signal coupling, tone stages |
| Electrolytic | microfarads to hundreds of microfarads | Power supply filtering, larger coupling caps — polarized |
| Tantalum | microfarads range | Compact power filtering — also polarized |
Full chapter: Resistors and Capacitors →
Reference Designators
| Prefix | Component |
|---|---|
| R | Resistor |
| C | Capacitor |
| Q | Transistor |
| D | Diode |
| U / IC | Integrated circuit, including op-amps |
| VR / P | Potentiometer |
Full chapter: Reading Schematics →
Bipolar Transistor Types
| Type | Symbol tell | Common pedal role |
|---|---|---|
| NPN | Arrow on emitter points outward | Most modern pedal designs — 2N3904, 2N5088 |
| PNP | Arrow on emitter points inward | Classic fuzz circuits, germanium-era designs — AC128, 2N2907 |
| Silicon | — | Predictable, temperature-stable, higher gain |
| Germanium | — | Lower turn-on voltage, softer clipping, temperature-sensitive |
Full chapter: Transistors and Diodes →
Common Op-Amp Chips
| Chip | Common pedal association |
|---|---|
| 741 | Early, simple designs — historically significant, now mostly superseded |
| 4558 / RC4558 | Tube Screamer and Tube Screamer-derived overdrives |
| TL072 / TL082 | Widely used general-purpose pedal op-amp — low noise, JFET input |
Potentiometer Taper Markings
| Marking | Taper | Typical use |
|---|---|---|
| A | Audio (logarithmic) | Volume, gain controls |
| B | Linear | Blend/mix controls, some tone and rate controls |
Full chapter: Potentiometers →
LED Resistor Values
R = (Supply Voltage − LED Forward Voltage) ÷ Desired Current.
| Supply | Typical red LED Vf | Target current | Resistor (rounded up) |
|---|---|---|---|
| 9V | ~2.0V | 10mA | 1kΩ |
| 9V | ~2.0V | 5mA | 1.5kΩ |
| 18V | ~2.0V | 10mA | 1.6kΩ |
Full chapter: LED Indicator Wiring →
Power Jack Convention
Nearly every pedal uses a 2.1mm barrel jack, center-negative — the inner pin is negative, the outer sleeve is positive. This is backwards from a lot of consumer electronics, so a generic "9V" wall adapter isn't safe to assume. Check the polarity diagram printed on the supply before plugging in anything unfamiliar.
Full chapter: Power Supply Conventions and Polarity Safety →
Jack Contacts
| Jack type | Contacts | Typical use |
|---|---|---|
| Mono (TS) | Tip (signal), Sleeve (ground) | Output jack |
| Stereo (TRS) | Tip (signal), Ring, Sleeve (ground) | Input jack — ring wired for the battery-cutoff trick |
3PDT Footswitch Pole Functions
| Lug row | Typical pedal function |
|---|---|
| Pole 1 (signal in) | Routes input signal to either the circuit or straight to output |
| Pole 2 (signal out) | Routes the circuit's output (or bypassed input) to the output jack |
| Pole 3 (LED) | Switches the status LED's ground connection (or supply) |