I was curious what would happen hypothetically if in a DC circuit consisting of only a push button switch and an inductor ( 10 ohms resistance) No capacitors, resistors or diodes.

What would happen to the current and voltage if you were able to push the button with your finger 5000 times per second?

If current increases with voltage and voltage is increased by the inductor wouldn't you technically be able to dial up any amount of voltage and current you desired?

 

No. You can’t get more out than you put in, no matter what you do.

 

A switching power supply does just that. But conservation of energy prevents you from creating both more current and a higher voltage.

It can create more current at a lower voltage, or higher voltage at a lower current only.

 

Yes, but - you can't get more POWER out than you out in...

 

The universal always true laws of entropy always apply. The 3rd rule is very obtuse but the first two can be stated very simply:

1. You can't win. Means you cannot get out more than you put in.

2. You can't break even. Means there are always losses.

So yeah you can get out more voltage than you put in, but at a lower current such that

Power in > Power out

 

It can create more current at a lower voltage, or higher voltage at a lower current only.

Essentially what Bob is saying is that you need to think in terms of watts.

In a PERFECT world Wattage is Voltage times Amperage. A given source of "Power" (in a perfect world) will give you 50 watts, which may consist of 25 volts and 2 amps. If you want higher amperage you can get 2.5V and 20A. OR you can get 1V and 50A. In all cases voltage times amperage equals wattage (power). However there's a limit to all things. You can't get infinite amps with 0V. There's a point where laws (Ohm's Law) can no longer support the hypothesis.

Now,

2. You can't break even. Means there are always losses.

In practical applications this is true. However, in reality, physics dictate there can be no losses. Just conversions. Suppose you have a 50 watt supply and you want to transform the voltage in either direction (up or down) - you have to use some sort of converter. You have a 50 watt at 25 volt supply but you need 12 volts. (Wattage is not the proper term for AC, VA is the proper term, but since watts is V x A, and for the sake of simplicity I'll continue to call it watts) You use a transformer. Suppose that transformer is 99% efficient. At 25 volts you were getting 2 amps but at 12 volts you're (in theory) going to get 4.17 amps. But you're going to lose something along the way. The transformer converts some of the power into heat energy. Some of the power into radiated electromagnetism. But assuming the transformer is nearly perfect (no such thing exists) your 4.17 amps will be 4.125A. You lose approximately 45mA. IF your transformer is a more realistic efficiency, and I don't know what that may actually be, 80 to 90% efficiency you will lose 417ma to 834mA. It doesn't vanish. It is converted into some other form of energy, whether it's heat or radiation or even sound energy, which is still energy. The wattage always remains the same. However, the user gets less of that energy because of losses. Other losses include the resistance of the wire itself. Wire is rated in size and ohms per foot (or metric measurements). That wire, when pushed to its limits will get hot, further reducing the delivered wattage. Some of it is dissipated as heat. And yes, even magnetic radiation.

There are practical limitations. The faster you drive the more wind resistance you encounter. Double the speed results in FOUR TIMES the wind resistance. At some point the losses become so huge they can't be supported. Same is true in electronics. There are limits to what you're going to get out of a circuit. Managing those losses is the art of engineering.

 

Pedantic, beware.

It is is actually energy that must be conserved, not power. Power is energy over time, so, you can use 1W for 100 seconds in and get 100W for 1 second out (minus losses.).

An example is a camera flash circuit, where it takes several seconds to charge, then the enery is all released in a fraction of a sevond.

But power is conserved if the in and out are supplied in the same time, i.e. continuously.

 

What you could get is voltage spikes, possibly a rather high voltageBut not more power.