Circuit calculators
Calculators for everyday electronic circuit design. Work out power consumption and running cost, resistor dividers, LED current limiting resistors, power supply efficiency, op-amp gain and RC filter component values.
Interconversion frequency and wavelength
It converts frequency to wavelength and wavelength to frequency. The higher the dielectric constant, the lower the propagation speed.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
RC filter / Cut off frequency
Low-pass filter Frequency at which the voltage becomes -3dB (0.707x)
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Resistor voltage dividing
The voltage at the midpoint when the voltage is divided by the resistor is determined. In actual design, the voltage at the midpoint will not be constant due to errors in resistance and voltage.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Advanced — Voltage tolerance, R1 tolerance, R2 tolerance
Derived values
- Division ratio
- 0.825
- R2 / (R1 + R2)
- Divider current
- 57.895 µA
- Vcc / (R1 + R2)
- Series resistance
- 57 kΩ
- R1 + R2
- Divider dissipation
- 191.05 µW
- Vcc² / (R1 + R2)
The output impedance (R1∥R2) is 8.246 kΩ. When driving an ADC sampling input or an op-amp, a higher value contributes more error.
LED lighting circuit design
Design a circuit consisting of a power supply, LEDs, and resistors. The actual components have variations in resistance and Vf, so there will be errors in the LED current.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Advanced — Max voltage, min Volatge, Vf Max and 2 more
Derived values
- Resistor dissipation
- 1.91 mW
- Worst case 3.77 mW
- LED dissipation
- 1.28 mW
- Vf × I
- Total dissipation
- 3.19 mW
- Vcc × I
- Voltage across R
- 3 V
- Vcc − Vf
Worst case 3.77 mW. With 50% derating you need a 7.55 mW rating or better, so a 1/16W (1005 / 0402) chip resistor is enough.
Comsumption from current and voltage
Power consumption From current and voltage
Power supply efficiency
Calculates the efficiency of the power supply from the input voltage and current and the output voltage and current.
Inverted amplifier circuit
Inverting amplifier circuit of OP amplifier
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Capacitance for pulse current
Find the capacitance of the capacitor that can store the pulse current.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Electricity costs from rated consumption
Calculate the electricity rate from the rated power consumption (xxW). 1kW = about 20 yen.
Convert discharge capacity to Power consumption
This is a calculator to convert the discharge capacity in mAh notation that you often see in batteries to power consumption (xxW). > The reference voltage is often conventionally 3.7V.
Resistance voltage drop
Calculate the amount of voltage drop from the resistance and current values.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli
Derived values
- Resistor dissipation
- 1 mW
- I² × R
- Recommended power rating
- 2 mW
- 50% derating
A 1/16W (1005 / 0402) chip resistor is enough.
Synchronous buck: efficiency, ripple, waveforms
Quick calculator for a synchronous buck (step-down) converter. It estimates inductor ripple and capacitor-only output ripple, and plots iL and vout ripple waveforms.
SI prefixes accepted (4k7 / 1M / 10m / 220). Upper-case M = mega, lower-case m = milli