# Current and Voltage Sources (With Definition) | Basic Electronics

When you first start learning about electronics, you hear about voltage and current sources as well as seeing their symbols and schematics. They will be used in nearly every circuit you come across So it’s good to have a fundamental understanding of what they do and their limitations. A voltage source is anything that creates a constant voltage differential between its two outputs. In general, you assume that one side is tied to ground or provides a reference voltage level. The other side is maintained at the rated voltage. Whatever that happens to be. An ideal voltage source will source whatever current is needed to maintain the voltage differential you’re aiming for. Looking at Ohm’s law, we have that voltage equals the current times resistance. As resistance drops to zero, voltage stay in constant Current becomes infinite, which is a problem. Even though real voltage sources such as batteries won’t create infinite current, They will produce a surprising amount and can cause burns or small explosions besides causing damage to the circuit itself. Voltage sources are much more common than current sources. Frankly, most anything you can think of will be a voltage source Batteries, DC power supplies or wall warts, electrical outlets, the USB port on your computer and a lot more things that I can’t think of. While current sources aren’t that common to most people, they do play an important role in semiconductor circuit design with things such as current mirrors and are even used in LED drivers and battery chargers. Current sources vary their voltage in order to meet the design requirements for the current needed by the circuit. They have the exact opposite safety problem of voltage sources. Taking Ohm’s law, you can see that if resistance goes to zero and current is held steady, then, the voltage will also go to zero. However, if resistance goes to infinity, which is an open circuit basically just not connecting the two halves of the circuit then, the voltage will go to infinity. Again, this is a problem. Although real current sources will not reach an infinite voltage, It is still a dangerous or destructive situation. I’ve mentioned, ideal and real power supplies for both the voltage and current sources And just want to clarify that we usually assume that our sources are perfect or ideal when we’re crunching numbers or running simulations. This makes things so much easier and usually is really close to reality. This means that they can source as much current or voltage as necessary to do their job and don’t have any built-in capacitances, resistances or inductances. Obviously, real power sources do have limitations and unwanted impedances. But again, we can very frequently ignore them. So in this video, we discussed voltage sources and current sources and briefly went over the potential dangers of both. We also touched on the difference between an ideal and real source and how to simplify things we can ignore certain factors at times. If you have any questions, leave it in the comments below and if you found this interesting or helpful, Please subscribe to our channel and like this video. To learn more, you can also go to our website, circuitbread.com