Procedure in Objective-C

Creation QR Code JIS X 0510 in Objective-C Procedure

1 Wire two lightbulb sockets in series with an ammeter and a low-voltage power supply Observe the correct polarity when wiring the ammeter 2 Screw the lightbulbs into the sockets Turn on the power supply Adjust the power control so that the bulbs are dimly lit 3 Unscrew one of the bulbs Record your observations in the data table 4 Screw in the bulb again and find the potential difference across both sets of bulbs by placing the positive probe of the voltmeter on the positive end of the circuit and the negative probe on the negative end of the circuit Record your data in the data table 5 Find the potential difference across each individual lightbulb by placing the positive probe of the voltmeter on the positive end of a bulb and the negative probe on the negative end of the bulb Record your data in the data table Repeat for the other bulb in series 6 Place the ammeter at various locations in the series circuit Record these currents in the data table 7 Wire the two lightbulb sockets in parallel with the low-voltage power supply and in series with an ammeter

because of the low currents used in this experiment This experiment should not be carried out using current from an AC circuit, as this current is deadly Handle wire ends with care as they may be sharp and could cause cuts

8 Screw the lightbulbs into the sockets Turn on the power supply Adjust the power control so that the bulbs are dimly lit Record the current shown on the ammeter in the data table 9 Check the potential difference across the entire circuit and across each lightbulb Record the values in the data table 10 Place the voltmeter probes across one of the lightbulbs Now unscrew one of the lightbulbs Record your observations of both lightbulbs, and record the current and potential difference read by the meters in the data table 11 Return the lightbulb you removed in the previous step to its socket Now unscrew the other lightbulb Record your observations of both lightbulbs, and record the current and potential difference read by the meters in the data table

1 Summarize the relationship among current, potential difference, and resistance in a series circuit 2 Summarize the relationship between current and potential difference in a parallel circuit

Repeat the experiment using lightbulbs of different voltage ratings (for example: 15 V, 30 V, and 60 V)

1 The lightbulbs in most homes all are rated for 120 V, no matter how many bulbs there are How is the ability to use any number of samevoltage bulbs affected by the way in which the bulbs are wired (series or parallel) 2 Why do lights in a home dim when a large appliance, such as an air conditioner, is turned on

1 Calculate the resistance of the pair of lightbulbs in the series circuit 2 Calculate the resistance of each lightbulb in the series circuit 3 How does the resistance of the pair of lightbulbs compare to the individual resistance of each lightbulb 4 How does the potential difference across the individual lightbulbs compare to the potential difference across the pair of lightbulbs in the series circuit 5 Calculate the resistance of each of the lightbulbs while they are in the parallel circuit How does this compare to the resistance calculated for the bulbs in the series circuit

Ground Fault Circuit Interrupters (GFCI)

A ground fault occurs when electricity takes an incorrect path to ground, such as through a person s body Charles Dalziel, an engineering professor at the University of California, was an expert on the effects of electric shock When he realized that ground faults were the cause of many electrocutions, he invented a device to prevent such accidents How does a ground fault circuit interrupter (GFCI) work

No current here Sensor electronics Trip coil To load Equal current Neutral Transformer No ground current