I do projects quite frequently, but the only problem is that sometimes I don't have the right component, and it takes to long to ship. I heard that some people change the values of their components (i.e. resistors, capacitors, coils). How can I do this in an example circuit.

I would really appreciate it if I could do this.

  • \$\begingroup\$ You have to understand how that specific component affects the circuit, i.e its functionality. Then you can estimate how the overall effect changes if you substitute that component with something similar, or available at hand. If you provided your example circuit and asked a specific question about the specific component, then maybe someone could explain you. Otherwise, your question does not have a simple answer. \$\endgroup\$ – Nazar Oct 2 '18 at 1:06
  • \$\begingroup\$ Depends of the purpose of the circuit, normally I have to change values but for precision I have to use parallel or serial components to achieve the required value. \$\endgroup\$ – Fernando Baltazar Oct 2 '18 at 5:33
  • \$\begingroup\$ Thank you very much. The answer makes sense. I will try your ideas. \$\endgroup\$ – Electro-Wizard Oct 2 '18 at 20:27
  • \$\begingroup\$ As one other note, if you live in North America and order from reputable vendors(digikey is the one I've used and Mauser is probably similar), parts will cost a bit more than from ebay or aliexpress, but you just might be shocked, shocked I say at how quickly the parts come. \$\endgroup\$ – K H Oct 2 '18 at 21:11
  • \$\begingroup\$ I see. I order from Gearbest.com. It takes around a month to come to Canada. \$\endgroup\$ – Electro-Wizard Oct 2 '18 at 23:50

Your question may end up getting removed as too broad, however, I'll give you a bit of direction.

For myself, I confine myself to working with circuits that I understand. You can learn a lot and maintain your interest without going into high level math (calculus, linear algebra) but I think you will find you benefit massively from learning the low level math involved (basic electrical theory is mostly algebra and trigonometry) and working with simple circuits and moving to more complicated ones as you understand each one. When I encounter design challenges that I don't yet have the math skills for or that I'm not familiar enough to deal with in reasonable time frame, I often resort to experimentation to get a short term answer. I can calculate how fast my MOSFET is able to switch, but it will take me much less time to breadboard a voltage converter and put my cheap oscilloscope on it. Past my oscilloscope's maximum frequency I have to go back to calculating. I could calculate the frequency necessary to get a smooth DC output from my LC filter, but heck, it's already on a breadboard, why don't I just vary the frequency while I watch the oscilloscope?

To get you started, I would suggest you learn(look up and make yourself a reference sheet):

Definitions of electrons and holes, charge(Avogadro's number, coulomb), voltage(volt), current(ampere), power(Watt/Horsepower)

Ohm's Law, Watt's Law

Formulas for series and parallel resistance

Kirchhoff's Laws

Edison 3 wire circuits

Relationship between DC and AC RMS voltage

Basic AC

Induction, transformers, AC motors/generators, DC motors/generators, Faraday's Law,

Capacitance, power factor, power factor correction, RLC resonance

Formulas for series and parallel Induction and Capacitance

DC RLC circuits

AC RLC circuits


I think if you work your way through this material, you will find by the end you should understand enough to do basic component upgrades and tweak resistors in circuits you understand, which will be a much larger category of circuits than it is now.

Edit: I just typed up a blurb on why you might be interested in spreadsheets and the internet ate it, so I'm going to have a bit of a break before I type it out again. When I suggest you make yourself reference sheets as you study, I mean something like this math one or this physics one. I stumbled upon them in ye local university bookstore and I was happy to part with a few maple dollars for well written all inclusive sheets, but even if you find something like them, writing out your own sheets as you learn things can be a great learning aid.

  • \$\begingroup\$ Thank you very much for the advice. It helps a lot. I definitely will make the spread sheet. \$\endgroup\$ – Electro-Wizard Oct 2 '18 at 20:26
  • \$\begingroup\$ Ermmm... I think you mean reference sheet, but since you mention it, spreadsheets are an incredible tool for the hobbyist so I'll add a little example about them to the post. Happy you found this useful. \$\endgroup\$ – K H Oct 2 '18 at 20:35
  • \$\begingroup\$ Oh great. Absolutely perfect. I'll check them out. \$\endgroup\$ – Electro-Wizard Oct 2 '18 at 23:49

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