HP 48GII

5-14 Equation Reference
RLC Current Delay (2, 11)
The phase delay (angle) is positive for current lagging voltage.
Equations:
Example:
Given: f= 1107_Hz, C=80_µf, L=20_ mH, R=5_Ω .
Solution:
ω=672.3008_r/s, φ s= -45.8292_°, φ p= -5.8772_°, XC=18.5929_Ω, XL=13.4460_Ω.
DC Capacitor Current (2, 12)
These equations approximate the dc current required to charge the voltage on a capacitor in a certain time
interval.
Equations:
IC
V∆
t∆
--------
⎝⎠
⎛⎞
⋅=
V∆ Vf–Vi–=t∆ tf ti⋅=
Example:
Given: C=15_µf, Vi=2.3_V, Vf=3.2_ V, I=10_A, ti=0_s.
Solution: ∆V=0.9000_V, ∆t=1.3500_µs, tf=1.3500_µs.
Capacitor Charge (2, 13)
Equation:
qCV⋅=
Example:
Given: C=20_µF, V=100_V.
Solution: q=0.0020_C.
DC Inductor Voltage (2, 14)
These equations approximate the dc voltage induced in an inductor by a change in current in a certain time
interval.
T A
N
φ
s
( )
X L X C
–
R
- - - - - - - - - - - - - - - - - - - - - - -
=
T A
N
φ
p
( )
1
XC
--------
1
XL
--------
–
1
R
----
-----------------------
=
X
C
1
ω
C
⋅
- - - - - - - - - - - -
=
X L
ω
L
⋅
=
ω
2
π
f
⋅ ⋅
=