Engineering & Automotive calculators (17)

Electronics (LED resistor, voltage divider, resistor colour code, RC, LC), batteries, wire voltage drop, solar output, decibels, horsepower and torque, stopping distance, engine and tire geometry, gear ratios.

Markdown version: /engineering.md · JSON: /api/v1/calculators?category=engineering

• LED Resistor Calculator — Computes the current-limiting series resistor for one or more LEDs in series from the supply voltage, LED forward voltage and desired current, then picks the nearest E12 and E24 preferred values, a safe (rounded-up) E24 value and the resistor power rating. (md · api)
• Voltage Divider Calculator — Computes the output voltage of a two-resistor divider (Vout = Vin·R2/(R1+R2)), the current through the chain and the power in each resistor, or solves for R2 when a target output voltage is given. (md · api)
• Resistor Color Code Calculator — Decodes the colour bands of a 4-band or 5-band resistor (IEC 60062) into its resistance, tolerance and min/max values, or encodes a resistance value into the 4-band (or 5-band) colour sequence. (md · api)
• RC Time Constant Calculator — Computes the time constant τ = R·C of a resistor–capacitor circuit, the times to reach 63.2 %, 95 % and 99 % of the final voltage (and the 5τ 'full charge' convention), the −3 dB cutoff frequency 1/(2πRC), and optionally the charge level after a given time. (md · api)
• Capacitors in Series and Parallel Calculator — Computes the total capacitance of a list of capacitors connected all in parallel (sum) and all in series (reciprocal of the sum of reciprocals), and optionally the energy stored at a given voltage. (md · api)
• LC Resonance Calculator — Computes the resonant frequency of an inductor–capacitor circuit from L and C, or solves for the inductance or capacitance needed to resonate at a given frequency, plus the angular frequency and characteristic impedance √(L/C). (md · api)
• Battery Runtime Calculator — Estimates how long a battery runs a load from its capacity (mAh, Ah or Wh), nominal voltage, the load in watts or amperes, and the usable depth of discharge (80 % for lithium-ion, 50 % for lead-acid by default). (md · api)
• Battery Charge Time Calculator — Estimates the time to charge a battery from its capacity in Ah, the charger current, the charge efficiency (default 85 %) and the starting state of charge, and reports the charging C-rate. (md · api)
• Wire Voltage Drop Calculator — Computes the resistance of a copper or aluminium conductor from its AWG gauge or cross-section and one-way length, then the voltage drop, percentage drop, voltage at the load and power lost for DC, single-phase or three-phase circuits. (md · api)
• Solar Panel Output Calculator — Estimates the energy produced by a photovoltaic array from the panel rating, number of panels, average peak sun hours per day and a performance ratio (default 0.75 for system losses), and optionally the electricity cost saved. (md · api)
• Decibel Calculator — Converts between a linear ratio and decibels using 10·log10 for power quantities or 20·log10 for amplitude quantities (voltage, current, sound pressure), and between dBm and milliwatts (0 dBm = 1 mW). (md · api)
• Horsepower, Torque and RPM Calculator — Solves the rotational power relation for whichever of power, torque or rotational speed is missing (HP = torque_lb_ft × rpm / 5252; kW = torque_nm × rpm / 9549) and reports the results in hp, PS, kW, lb·ft and N·m. (md · api)
• Stopping Distance Calculator — Computes the reaction (thinking) distance, braking distance and total stopping distance of a vehicle from its speed, the driver's reaction time and either a road-condition friction coefficient or a given deceleration, in metres and feet. (md · api)
• Engine Displacement Calculator — Computes engine displacement from bore, stroke and cylinder count (V = π/4 × bore² × stroke × cylinders) in cc, litres and cubic inches, plus the per-cylinder volume and bore/stroke ratio. (md · api)
• Compression Ratio Calculator — Computes the static compression ratio of a piston engine from bore, stroke, combustion chamber volume and the optional piston dish/dome, deck clearance and head gasket volumes: CR = (swept + clearance) / clearance. (md · api)
• Tire Size Calculator — Parses a metric tire code such as 225/45R17 into section width, aspect ratio and rim size, computes sidewall height, overall diameter, circumference and revolutions per kilometre and mile, and optionally compares a second size (diameter difference and speedometer error). (md · api)
• Gear Ratio and Speed Calculator — Computes vehicle road speed in km/h and mph from engine rpm, transmission gear ratio, final-drive ratio and tire diameter (or tire code), plus the overall ratio, wheel rpm, speed per 1000 rpm and, optionally, the engine rpm at a given road speed. (md · api)