Capacitors

Question 1

RC Time Constant

Answer 1

Calculates Charging/Discharging Time

This is denoted by TAU

Tau = Resistance * capacitance
Tau = Ohms * Fardas

After 5 of these increments, or 5 Taus rather, the Capacitor is considered fully charged

Also, remember to convert your Ohms! If 10kOhms multiple 10,000 lol

Question 2

How do you convert microfarads to farads?

Answer 2

divide microfarads by 1,000,000

Question 3

You have 47k Ohms and a 10uF capacitor.
How long until it’s fully charged?

Answer 3

47,000 * (10 / 1,000,000)
Tau is .47 seconds
.47 * 5
2.35 seconds

Question 4

You have 5k Ohms and a 220F capacitor.
How long until it’s fully charged?

Answer 4

5,000 * (220/1000000)
Tau = 1.1
1.1 * 5
5.5 seconds

Question 5

In a triple 5 times in astable mode, we have two resistors of 100ohms each that lead from vcc to the capacitor. How long until it charges (remember, technically you’d need to find 2/3’s here of full charge because that’s as far as the timer would allow it to get)
The capacitor is 45uf

Answer 5

100 + 100 = 200 ohms <- this would be in series so we add them
200 * (45 / 1,000,000)
.045 seconds (45 miliseconds)