PHY 232
Your 'the rc circuit' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Your comment or question: **
** Initial voltage and resistance, table of voltage vs. clock time: **
1.72V, 3ohms
** Times to fall from 4 v to 2 v; 3 v to 1.5 v; 2 v to 1 v; 1 v to .5 v, based on graph. **
10.2938938sec
7.2183828sec
5.281828sec
1.2934929sec
There is a spike of a drop at the end for the voltage to fall
** Table of current vs. clock time using same resistor as before, again starting with 4 volts +- .02 volts. **
3.2, 10.200333sec
2.8, 8.3912923sec
2.5, 7.2812828sec
2.3, 6.3828288sec
** Times to fall from initial current to half; 75% to half this; 50% to half this; 25% to half this, based on graph. **
10sec
5sec
2 sec
0.66sec
There seems to be a spike. It is almost like a roller coaster drop. Right before the drop it slowly goes down, but soon it spikes and goes straight down
** Within experimental uncertainty, are the times you reported above the same?; Are they the same as the times you reports for voltages to drop from 4 v to 2 v, 3 v to 1.5 v, etc?; Is there any pattern here? **
more or less the times seem the same. I see a proportional relationship
** Table of voltage, current and resistance vs. clock time: **
1.7V, 1.2, 100, 15.02sec
This is the voltage, current, and resistance that went in the time.
** Slope and vertical intercept of R vs. I graph; units of your slope and vertical intercept; equation of your straight line. **
m = 0.23
ohms/second
y=0.23x + 1.22221
** Report for the 'other' resistor:; Resistance; half-life; explanation of half-life; equation of R vs. I; complete report. **
250
15.224343sec +- dt
t is the time measured that I found. The uncertainty in time dt would be about 0.2223sec for how accurate the timer program is and my clicking the mouse
** Number of times you had to reverse the cranking before you first saw a negative voltage, with 6.3 V .15 A bulb; descriptions. **
26
I have no idea whether my estimate was accurate or not.
The bulb flickers a lot, this could be the different resisitance being used. The bulb is affected by how quickly I turn the generator. If I turn it the other way it depends on its position how much of a change there will be. It is possible nothing would change.
** When the voltage was changing most quickly, was the bulb at it brightest, at its dimmest, or somewhere in between? **
in between
The brightness of the bulb changes most frequently when there is a change in the capacitance. Changing one changes the other.
** Number of times you had to reverse the cranking before you first saw a negative voltage, with 33 ohm resistor; descriptions. **
27
I am not sure if it was accurate or not, but I would guess that the true answer would be + or - 5.
I discharged the capacitor, closed the switch, cranked the generator, and reverses cranking until I got a negative voltage
** How many 'beeps', and how many seconds, were required to return to 0 voltage after reversal;; was voltage changing more quickly as you approached the 'peak' voltage or as you approached 0 voltage; 'peak' voltage. **
5 beeps, 3.8seconds
Voltage changed more quickly as I approached zero voltage(when it diminished)
7.1 V is the maximum
** Voltage at 1.5 cranks per second. **
2.7V
** Values of t / (RC), e^(-; t / (RC) ), 1 - e^(- t / (RC)) and V_source * (1 - e^(- t / (RC) ). **
1.7, 2.1, 1.6, 1.4
These were obtained using the equations given earlier
** Your reported value of V(t) = V_source * (1 - e^(- t / (RC) ) and of the voltage observed after 100 'cranks'; difference between your observations and the value of V(t) as a percent of the value of V(t): **
2.7765V
.21
** According to the function V(t) = V_source * (1 - e^(- t / (RC) ), what should be the voltages after 25, 50 and 75 'beeps'? **
100 beeps
** Values of reversed voltage, V_previous and V1_0, t; value of V1(t). **
1.3V, 1.2V, 16t, 1.22
1.22V
These are the four numbers I have down and the final is found from v1(t)
** How many Coulombs does the capacitor store at 4 volts? **
Coulomb = Farad * Volt
Coulomb = Farad * 4volts
(The capacitor has a value of about 1.5F)
Coulomb = 1.5F * 4V = 6 C
** How many Coulombs does the capacitor contain at 3.5 volts?; How many Coulombs does it therefore lose between 4 volts and 3.5 volts?; **
Coulomb = 1.5F * 3.5 V = 5.25 C
So it loses about 6 -5.25 = 0.75 C
** According to your data, how long did it take for this to occur when the flow was through a 33-ohm resistor?; On the average how many Coulombs therefore flowed per second as the capacitor discharged from 4 V to 3.5 V? **
16seconds, 0.66
This is the average time and coulombs
** According to your data, what was the average current as the voltage dropped from 4 V to 3.5 V?; How does this compare with the preceding result, how should it compare and why? **
3ohms
Resistance changed as the voltage dropped
** How long did it take you to complete the experiment? **
175 minutes
** **
&#This looks good. Let me know if you have any questions. &#