Resistors

From what I know it would be the opposite, as the Time Constant (RC, Resistance * Capacitance) would be larger resulting in a longer discharge time.

The lamps wouldn't light as brightly, because not as much current would get through, but they would light for longer; the voltage decreases at a slower rate due to the increase in Resistance.

If you don't believe me have a fiddle about with this website chucking in different resistor values, and see what happens to the voltage levels at different times...http://hyperphysics.phy-astr.gsu.edu/HBASE/electric/capdis.html#c2

Although this is not in my syllabus, your right.

Is there another way explaining this without mentioning the time constant?

Also, what would happen in part b?

thanks

Part b The Capacitors would charge up slower due to the increase in resistance. Without any resistance a Capacitor would essenitally charge instantly, but with it it charges up at a slower rate.

What exam board are you on that teaches you about Capacitors but not any of the charging/discharging equations???

Although this is not in my syllabus, your right.

Is there another way explaining this without mentioning the time constant?

Also, what would happen in part b?

thanks

Why would the voltage decrease at a slower rate because of an increased resistance?

Is there an equation to prove this?

Are You taught C = Q/V?

If so then if you subsitute in Q = It, and V = IR then you end up with

C = t/R.

In other words for 1 Coulomb of charge to discharge from the Capacitor, when the circuit has a resistance of 4 Ohms it will take 4 seconds.

If the resistance then increases so will the time it take for the Capacitor to discharge that Coulomb.

I think !

It all relates to the time constant. The equation for a discharging Capacitor is:

Vc = Vs e ^(-t/RC)

Where Vc is the Capacitor Voltage
Vs is the Supply Voltage
e is the mathematical constant e
t is the time taken
and RC is the time constant.

The higher RC the longer the Capacitor takes to discharge.

Ok Thanks. So could you please check through my final answers:
a)
"The lamps wouldn't light as brightly but would be lit for a longer duration; the resistor will increased the time it takes for the capacitor to discharge"

b)
"The capacitor would charge up at a slower rate, so it will gain less charge and so the light bulb will be lit for less time."

That seems right to me.

That seems right to me.