Bench Calculators, Component Decoders & RF/IR Utilities
Instant browser-based electronics calculators and component decoders covering 4-band and 5-band through-hole resistors, SMD resistors (3-digit, 4-digit, R-notation, EIA-96), ceramic/film/SMD capacitor codes, an interactive V/I/R/P Ohm's Law & Power solver, a 555 Timer astable frequency & live waveform calculator with E24 LED series resistor sizing, plus non-invasive IR/RF remote identification and wireless protocol sheets.
f = 1.44 / ((R1 + 2·R2) × C1)Core Capabilities & Coverage
- Resistor & Capacitor Calculator: 4-band and 5-band interactive color decoder with live SVG resistor body and tolerance min/max range, plus SMD resistor (3/4-digit, R-notation, EIA-96) and capacitor (picofarad 3-digit & tolerance letter) decoders.
- Ohm's Law & Power Wheel: Enter any two known parameters among Voltage (V), Current (I), Resistance (R), and Power (P) to solve the remaining two with explicit algebraic formula breakdowns.
- 555 Timer & LED Calculator: Real-time astable pulse frequency, period, duty cycle, and high/low time solver with dynamic SVG square-wave preview, paired with an LED series resistor calculator recommending the nearest E24 standard resistor and safe wattage rating.
- IR vs. RF Remote Identifier & RF Protocol Reference: Non-invasive decision tree using a phone camera, tape test, and AM radio to classify handsets, linked to 315/433/868 MHz, 38 kHz IR, BLE, and LoRa deep-dive sheets (/protocols/{slug}).
Step-by-Step Workbench Workflow
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1
Decode Through-Hole & SMD Resistor / Capacitor Markings
In the Resistor & Capacitor Calculator, toggle 4-Band or 5-Band mode and select each band color to read nominal resistance and min/max tolerance limits—or type an SMD code (e.g., 472, 4R7, 01C, or capacitor code 104K) to get instant Ω, pF, nF, and µF conversions.
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2
Solve Circuit Voltage, Current, Resistance & Power Dissipation
Open the Ohm's Law Wheel, enter any two known measurements (for example, a 5V rail dropping across a 47Ω resistor, or a regulator dissipating 1.5W at 250mA), and click Calculate to view the exact derived values and equations used.
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3
Design 555 Clock Pulses & Size LED Current-Limiting Resistors
In the 555 Timer & LED Calculator, adjust R1, R2, and C1 to shape your astable clock/reset pulse while watching the live SVG duty-cycle waveform update. Below it, enter Supply Voltage (VS), LED Forward Voltage (VF), and target current (IF) to get the exact E24 resistor and 2× safety-derated wattage.
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4
Classify Unknown Remote Handsets & Inspect RF/IR Protocols
Use the IR vs. RF Remote Identifier to run 60-second non-invasive checks before opening a handset enclosure, then jump directly into the RF & Wireless Protocol Reference to inspect carrier frequencies, OOK/ASK/FSK modulation, and encoder chipsets (PT2262, EV1527, NEC 38kHz).
When replacing a current-limiting or power-dropping resistor on a vintage board, always check the Power (P) readout in the Ohm's Law or LED calculator and select a physical resistor rated for at least 2× the calculated dissipation (e.g., use a 0.5W resistor if calculated dissipation is 0.22W) to prevent heat scorching the PCB fiberglass.
Reading 5-Band Metal Film Resistors Backwards & 104 vs. 100pF Confusion: Precision 5-band resistors on blue bodies often have a brown (1%) or red (2%) tolerance band that looks identical in width to Digit 1—measure with an ohmmeter if unsure! On ceramic decoupling caps, "104" means 10 × 10⁴ pF = 100 nF (0.1 µF), whereas "100" means 10 × 10⁰ pF = 10 pF.