Here are calculators and converters for the things you’ll calculate most often when you build circuits: from Ohm’s law and resistor values to LED resistors, timers and power supplies. Each one shows the formula it uses, so you can learn how to do it by hand too.
Basics
Ohm's Law CalculatorFind voltage, current, resistance or power from any two of them.
Voltage Divider CalculatorFind the output voltage of two resistors in series.
Series and Parallel Resistor CalculatorThe total resistance of resistors in series or in parallel.
Resistor Color Code CalculatorRead a resistor's value from its color bands.
SMD Resistor Code CalculatorRead a surface-mount resistor's value from its code, like 472.
Components
LED Resistor CalculatorThe resistor you need in series with your LEDs.
Transistor Switch CalculatorThe base resistor for switching a load with an NPN transistor.
Zener Diode CalculatorThe series resistor and power ratings for a zener regulator.
Capacitor Code CalculatorRead a capacitor's value from its code, like 104.
Capacitor Value ConverterConvert between pF, nF, µF and F.
Timing and Filters
555 Timer CalculatorThe frequency or pulse length of a 555 timer circuit.
RC Time Constant CalculatorCharge time and filter cutoff frequency of a resistor and a capacitor.
Power
Smoothing Capacitor CalculatorThe capacitor you need after a rectifier, and the ripple you get.
Battery Life CalculatorHow long a battery will last in your circuit.
What Calculator Would You Like To See?
If there are any calculators or converters that you’d like to see here, let me know in the comments below.
I want to learn electronics I'm 69 years old and guess what you're never too old to learn teach me
You're never too old (or too young) for electronics!
A frequency to antenna length , quarter wave, half wave and full wave would be super handy for those of us who dabble in amateur radio.
Cheers , Brewski
Tengo 69 años y tengo mucho interés en aprender
Cómo funciona la electrónica muchas gracias
esta mucho bueno.
You should have learned this when taking your technician class license.
I'm 63 and am excited to learn as well.
77 here so you're not alone.
I am also in the same age and trying to learn.
I appartain electric studies
I want to learn electronics that's all thank you
Great =)
I want to learn more about electronic, I am 86 yrs young and never to late to learn more. I think it is good to keep the old "grey cells" active, or, get them rejuvenated a little.
Great to hear, you're definitely never too old!
It would be nice to see an LED Resistor (Par/Ser) calculator.
Thank you for your efforts
Thanks, I'll add that soon!
I've been interested in electronics since I was a teenager. But was always afraid with all the components involved it would be far beyond my brain capacity. Right now I'm 51 I'm a carpenter iron worker mechanic I can plumb and wire a house including the breaker box I can fix HVAC systems. I recon I have enough room for some basic electronics at least!
With your background, you got this! What’ll help you going forward, is your willingness to learn. As long (and this is my opinion) as you can keep your electronics knowledge, current, by being, “hands-on”, this will give you the foundation to continue building upon what you’ve learned.
Good luck and remember, breadboard, breadboard, breadboard
cCHci se naučit elektrpniku
I'm 85 and spent a lifetime in electronics, started dabbling at around age 10 and spent most of my working life in the field. Still dabbling and glad to have a really useful set of calculators which save time and effort. (I guess I've grown lazy!)
Thank you for your resource.
I proud of you mr.Bill. I am also 64 years old.
Great website and projects. Teachers of electronics may be interested in looking at our apps for teaching.
You are very geneous teacher of an electronics
yes. i want those circuits dymistified.
spent 30 years working in pcb fabrication and 15 years in Electronic Assembly. Learned a lot thru association with electronics in this 45 year period, but finding this website has taught me more about electronics in the past year, since my retirement, than I previously learned thru my jobs. Thank you for this wealth of knowledge. aT 71, I never tire of electronics.
Glad to hear =)
Hi - if you could please - I would like to an inductance calculator for rf coils - I recently dug up a tracking transmitter circuit from long ago and it calls for two " air wound 1uH coil - doesn't call diameter nor length nor turns - just 1uH. Other calculators want all this info - yet if a calculator could work it backward like plug in 1uH and the calculator spits out the rest ?? Thanks !!!
I liked all of the interest and friendly comments.
Very good it's the best, for all diy circuit maker
الموقع ممتاز لزيادة ما تعلمته في الماضي
ميكاترونك مجال ممتاز يحوي على الإلكترونيات
how to calculate capacitor value to get required current with 230v'50 Hz A/C supply.
a wish list.... capacitor-joules-amperes-voltage calculator
2. photoflash tube lightoutput or capacity based on length of flash arc and diameter of tube
3. simple calculator that tells you which wire gauge to use, how many turns, former dia, and coil length, in order to arrive at a value for a crossover air-cored coil for loudspeaker crossover unit.
These do exist in different locations. It would be nice to have them all on one site
Let me test the knew laptops to make sure they are up to date
Iuuu
Calculating the magnitude, the values of its real part, imaginery part with sign (inductive or capacitive) and the phase angle of an impedance (R+jX) for a circuit of R, L and C connected in series or parallel.