According to its design specification, the timer circuit delaying the closing of an elevator door is to have a capacitance of 33.0 µF between two points A and B.(adsbygoogle = window.adsbygoogle || []).push({});

(a) When one circuit is being constructed, the inexpensive but durable capacitor installed between these two points is found to have capacitance 35.4 µF. To meet the specification, one additional capacitor can be placed between the two points. To meet the specification, one additional capacitor can be placed between the two points. Should it be in series or in parallel with the 35.4 µF capacitor? (in series)

What should be its capacitance?

(b) The next circuit comes down the assembly line with capacitance 32.5 µF between A and B. What additional capacitor should be installed in series or in parallel in that circuit, to meet the specification? (parallel)

a) Ct = C1 +C2

33uF = 35.4uF + C2

isn't C2 = 33fF - 34.5uF ??

b) (1/Ct) = (1/C1) + (1/C2)

isnt (1/C2) = (1/33uf) - (1/32.5uF) ??

Im lost here...any help will be apprecieated

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Help with total capacitance in parallel and in series

**Physics Forums | Science Articles, Homework Help, Discussion**