Electronics & DIY
Ohm's law, voltage divider, LED resistors, Arduino
Subtopics
Ohm's law
1 tools
Voltage divider
1 tools
LED resistors
1 tools
RC/RL circuits
1 tools
Power supply
1 tools
Batteries
1 tools
Soldering
1 tools
Arduino/ESP
1 tools
Sensors
1 tools
Multimeter
1 tools
Device repair
1 tools
PCB design
1 tools
Project enclosure
1 tools
Wires & cross-sections
1 tools
Mains safety
1 tools
Component marking
2 tools
Oscilloscope
1 tools
Lab PSU
1 tools
DIY smart home
1 tools
Radio amateur's glossary
1 tools
Calculators
Ohm's law
V, I, R, P — any two → the rest
Voltage divider
pick R1/R2 (E24) for target V
LED resistor
(Vs−Vf)/I + E24 value + power
RC circuit
τ=RC: charge time to 63/90/99%
PSU sizing
Load list → total power and PSU with headroom
Battery runtime
Ah × V → Wh with DoD and efficiency
Soldering guide
Solder + work type → tip temp and tips
Arduino & MCUs
Arduino Uno, Nano, ESP32, Mega boards — specs, key pins, which projects
Sensor wiring
Reference: power, interface, sensor pins
Multimeter measurements
How to measure voltage, current, resistance, diodes — modes, probes, steps, warnings
Fault diagnostics
Symptom → check sequence: dead, overheating, unstable, charging issues
PCB trace width
Current → trace width per IPC-2221
Project enclosure
Board dims → minimum enclosure with clearances
Wire gauge
by current and voltage drop over length
Mains safety
Mains work rules — checklist
SMD code
Resistor code (3/4 digits, EIA-96) → value
Resistor colors
bands ↔ value: 4- and 5-band code
Oscilloscope basics
Probe hookup, basic measurements, digital signals, common traps
Lab power supply
CC/CV modes, lab PSU specs, power headroom sizing
DIY smart home
Scenario → component list and budget
Electronics glossary
Pull-up, PWM, ADC, ESR, MOSFET, I2C, SPI, UART — terms in plain language