Electronics calculators
Quick answers with the formula and a worked example, and a link to build the circuit on the simulator.
Ohm’s law calculator
Volts, amps, ohms and watts from any two
LED resistor calculator
The series resistor for one LED or a string
Voltage divider calculator
Vout from two resistors, or the resistor for a wanted Vout
Series and parallel resistor calculator
Total resistance of resistors in series or in parallel
RC time constant calculator
τ = RC, charging time and cut-off frequency
Reactance and resonance calculator
XL, XC and the LC resonant frequency
555 timer astable calculator
Frequency and duty cycle of a 555 oscillator
PCB trace width calculator (IPC-2221)
How wide a copper trace must be for a current
Battery runtime calculator
How long a battery runs a load
Solar panel and battery size calculator
Panel watts, battery size and controller current for a daily load
Wire size and voltage drop calculator
Voltage drop in a DC or single-phase run, and the size to use
Breaker and wire size calculator (Philippines)
The breaker and the mm² THHN or PDX for an appliance or a circuit, by the Philippine Electrical Code
Resistor colour code calculator
Read a 4-band or 5-band resistor