# Tagged Questions

62 views

### Find current flowing over an element given charge as a function of time

This should be pretty basic but I want to clarify some: I = dQ/dt, so that means that I is the derivative of q(t) right? So if I'm given q(t) = (7t^2 - 2t +3) pC and told that time is dimensionless ...
181 views

### Discharge and charge rates of a capacitor - Comparing Energy Movements

This is a really simple question. But I'm seeing some confusing behavior in an experiment I'm trying to make sense of. So I'm trying to see if my understanding of theory is wrong. Wikipedia says: ...
605 views

### Do electrons actually flow when a voltage is applied?

It's said in books that a circuit is a closed path and thus that electrons come back to the source. If that's the case, what would happen when there were an earth fault in a circuit? How would the ...
423 views

### 220V 0.2A converted to 12V 5A, where are the missing amperes?

I have an AC adapter at home that reads (roughly) the following: uses 220-240v AC 50Hz at 0.2A produces 12V DC at 5A I'm a little surprised that it uses 0.2 amps and produces upto 5. Here's what ...
169 views

### What parameters affect battery charge time?

What parameters affect battery charge time? For example if we're interested in designing a charger for mobile batteries, what parameters should be considered? What happens if a little higher voltage ...
576 views

### Understanding voltage and current

While reading "Electronics for dummies" went through the following block and I realised that I have some uncleared concepts about electricity: Electrostatic discharge involves very high voltages ...