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Hello, Can you please help with the following project : I want to add 2 electric currents one from source 1 and the other from source 2 and get the total current .What type of device should I use to get the total currents from 2 differently current sources ?Thanks so much for help.
Question Date: 2013-04-28
Answer 1:

Thanks for your question! Let’s assume for simplicity that your power source is direct current (DC) and not alternating current (AC)—if it were AC then this would add a whole other level of complication. It would be okay to simply combine two current sources in parallel *if and only if* you know that they are of the same voltage. Otherwise, terrible things can happen, such as the voltage mismatch leading to one power source overcharging the other and causing a meltdown or even dangerous explosions!

In reality, it is actually very difficult to ensure that two power sources have the exact same voltage—even with things like commercial batteries, the voltage each battery outputs changes over its lifetime.

Since I don’t know too much of your circuit layout and design, I can recommend right now that your best solution may just to think about the design of your circuit in terms of voltage gains and drops. In this scenario, treat each power source as a voltage source instead of a current source. You should find that analysis will be easier because of this. In general, putting two power sources in series is much safer, and you will find that the current output will vary depending on the loads (resistors, buzzers, LEDs, etc.) of your circuit. You can apply Kirchhoff’s circuit laws of current and voltage to determine how much current is flowing throughout your circuit.

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