I am just starting to dabble in electrical engineering and circuit design, so forgive my ignorant questions. I am trying to get started building a very simple experiment with my son and I'm not sure where to even begin, so any guidance at all is very much appreciated.

First, we have a 12VDC 2.8A 3500rpm 21W motor with a 12VDC power supply. (Edit: I'm not stuck to this particular motor or voltage in any way, if we can achieve the same effect with something smaller that is fine as well.) What I'd like to do is create a momentary increase in the supply voltage to increase the speed of the motor for a second or two. Almost like a turbo booster button.

My first thought was a secondary power supply in series with the primary 12VDC connected with a momentary SPDT switch. Seems simple enough

But I'd really like to charge up the "turbo booster" button so he can learn about (small-ish) capacitors. But I'm at a loss on how to supply voltage to the capacitor from a secondary power source and then discharge it in the series to quickly burst the speed of the motor until the capacitor is discharged and the SPDT button is released to recharge the capacitor. I'm sure there is a very simple answer to this, but I can't seem to find a good place to start.

Thanks in advance!

  • 1
    \$\begingroup\$ But I'd really like to charge up the "turbo booster" button What does that mean? What are you trying to achieve? You'd need a very large capacitor with a very large value to see its effect with a 12 V, 2 A motor. Chances are, you will not be able to do what you want to achieve. If you want to learn about electronics, get a book or a kit and follow the instruction. Doing things "on your own" as a beginner often leads to things not working and dissapointments. \$\endgroup\$ Jan 5, 2021 at 22:03

1 Answer 1


Putting two different power supplies in series will most likely lead to the failure of one of them, due to power mismatching.
But for a simple non-permanent demo it should work (for a little while).

You could also do something similar with batteries.

If you are as new to electronics as you say you are, I'd probably not go down the path of the charging up a capacitor for a motor of this size. It'll get complicated fairly quickly.

While not as fun as a motor, you could do something with an automotive incandescent light bulb. Power it with 8V then make it go brighter with 12V. That would be easier to achieve with a capacitor charge/discharge system.


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