Electronics Hobbyist Kit: Meters, Signals, Gauges
36 toolsFor people who solder and build circuits: size a resistor or a divider, a PCB trace or a 555 timer, test a circuit in a simulator, measure current in a cable, RPM and flicker, feed in a test signal and size the motors and battery of a robot.
Electronics
Delay-line reservoir computing
Move the feedback gain and watch the reservoir’s memory change.
Ohms Law Calculator
Calculate voltage, current, resistance, and power instantly. Interactive Ohm's Law wheel, animated circuit diagram, and practical presets.
Resistor Color Code Calculator
Decode resistor color bands or find band colors by resistance value. Interactive SVG, 4/5/6 bands, tolerance range, E-series matching.
Capacitor Code Decoder
Decode 3-digit capacitor markings to pF/nF/µF or find the code from a capacitance value. Voltage ratings, tolerance codes, unit converter.
SMD Code Decoder
Decode SMD component markings — 3-digit, 4-digit, and EIA-96 codes for resistors and capacitors. Reverse lookup and package size reference.
LED Resistor Calculator
Calculate the current-limiting resistor for any LED circuit. Color presets, series/parallel arrays, power warnings, nearest E24 value.
Voltage Divider Calculator
Calculate voltage divider output, find R1/R2 from desired Vout, E24 matching, load effects, tolerance analysis, and power dissipation.
Wire Gauge Calculator (AWG)
Find the right wire gauge for your project. AWG↔mm² converter, voltage drop calculator, ampacity tables, copper and aluminum support.
PCB Trace Width Calculator
Calculate minimum PCB trace width for a given current using IPC-2221 standard. Supports internal/external layers, multiple copper weights, and voltage drop.
555 Timer Calculator
Calculate NE555 timer circuits — astable and monostable modes. Frequency, duty cycle, waveform preview, and reverse component calculation.
RC Circuit Calculator
Time constant τ = RC, capacitor charge and discharge time, RC filter cutoff frequency, E24 component picker and the spread component tolerance adds.
Base Resistor Calculator
Base resistor for a transistor switch: base current with a saturation margin, E24 value rounded down and resistor power.
Circuit Simulator
Build and simulate electronic circuits in your browser. Drag-and-drop components, draw wires, real-time voltage and current readouts.
Breadboard Simulator
A virtual solderless breadboard: plug parts into holes, run jumpers — the circuit really computes.
Perfboard Layout
Lay parts out on a solder board, draw the traces and check the circuit before you pick up the iron.
Battery Calculator
Runtime, charge from voltage and charging for 12 V, AGM, gel, LiFePO4, Li-ion and LiPo
Battery Identifier
Measure a battery on your calibrated screen, or print a true-to-size gauge — then read which battery it is.
Robotics
7 more in this category →Gear Ratio Calculator
Calculate gear ratios, RPM and torque for multi-stage gear trains used in robotics, RC vehicles and mechanisms.
Servo Torque Calculator
Enter payload mass and lever length to calculate the required servo torque.
Quaternion & Rotation Converter
Select an input format, enter values, and all other representations update live.
Stepper Motor Calculator
Configure stepper motor steps/mm for 3D printers, CNC machines, and robotics firmware.
Robot Speed & Odometry Calculator
Enter wheel diameter and RPM to get linear speed, km/h, mph, and odometry metrics instantly.
Serial Monitor
Connect Arduino, ESP32, or any serial device and monitor incoming data live in your browser.
Measuring
Gyroscope drift meter
How long your phone still knows which way it is pointing.
Cable current meter
Lay the phone on an appliance’s cable and see whether current is flowing, and how much.
Light flicker meter
Point the camera at a lamp or a screen and read its flicker frequency, depth and risk level.
RPM Meter
Five ways to read rotation speed: by sound, by a marker in the camera, by the phone's gyroscope, by screen strobe and by a printable strobe disc. Plus lamp flicker and PWM.
Generation
Tone Generator
Generate precise audio tones, sweep frequencies, mix oscillators, play DTMF phone tones, export WAV. Web Audio API.
Ultrasonic Generator
Generate ultrasonic frequencies beyond human hearing. Up to 48 kHz with 96 kHz sample rate. Real-time spectrum analyzer.
Morse Code Generator
Convert text to Morse code with audio playback. Adjust speed and tone, download as MP3 or WAV.
DTMF Generator
Generate and decode telephone touch-tones with ITU-T Q.23 precision — keypad, sequence player, microphone decoder, multi-region call-progress tones, WAV/MP3 export.
Samples & Test Files
Sine Sweep WAV Generator
Generate log or linear sine sweep WAV files for REW, ARTA and room measurement. 20 Hz–20 kHz, 44.1/48/96 kHz, 16/24-bit, full channel routing.
TV Test Pattern Generator
TV calibration patterns for projectors and displays — SMPTE bars, PLUGE, grayscale, focus star, HDR window, overscan. PNG up to 8K plus MP4 loops.
Other tools
Charger and cable tester
Find out how many watts your charger is really putting into the phone.
ZX Spectrum tape
ZX Spectrum tapes in your browser: TZX/TAP to audio for loading into a real Spectrum, cassette recordings back to TAP, tapes from your own BASIC.
Morse Code Decoder
Decode Morse code from audio — record from microphone or upload a file. Real-time analysis to text.