I red that a capacitor blocks DC but passes AC Why is it when I hook up a capacitor with a LED the LED lights up and pulses depending on the capacitor rating. If a capacitor blocks DC how come the LED lights up??
The LED lights from the charging current through the capacitor. Once the cap is charged the LED turns off since no further current flows. The point is that capacitors block DC only after they are charged to the steady-state DC value. Any change in DC level is coupled through.But what actually make the LED light up? Just like MrChips explained the effects of the capacitor and not the DC itself? So why do we find so many capacitor in electronics if it blocks DC I know in an audio circuit it would let the audio trough but most circuits have capacitors and the source is DC
Voltage doesn't go through anything. It's a potential from one point to another. When you apply a voltage across a capacitor a current flows until it is charged to the voltage potential being applied. If you do nothing else it just sits there and the LED won't light. But if you allow it to charge in one direction, and then allow it to charge in the other direction, you have current flowing back and forth. And, hence, the LED will light up.So there's no actual voltage going through the capacitor?
As crutschow said, if you connect a capacitor in series with a DC power source, you'll prevent current from flowing (once the capacitor is fully charged). But capacitors aren't always used in series, often times they're used in parallel. For example, a capacitor connected between the 5V and GND pins of a microcontroller does not allow DC current to flow through it, and that's a good thing (else you'd be shorting 5V to ground). But since it allows alternating current through, any quick changes (spikes or dips) in the voltage will be allowed through and away from your load (the uC, in this case).So why do we find so many capacitor in electronics if it blocks DC I know in an audio circuit it would let the audio trough but most circuits have capacitors and the source is DC
I think I'm starting to understand the DC blocking Let's go a few step back!!! So basically what do the work or make a LED light up or a motor to work is the amperage and not theVoltage doesn't go through anything. It's a potential from one point to another. When you apply a voltage across a capacitor a current flows until it is charged to the voltage potential being applied
An LED only lights if a current goes through it. It needs a minimum voltage across it, sure, but its brightness is determined by how much current flows through it.I think I'm starting to understand the DC blocking Let's go a few step back!!! So basically what do the work or make a LED light up or a motor to work is the amperage and not the
voltage???
by Jake Hertz
by Aaron Carman
by Aaron Carman
by Aaron Carman