[Part 2]- Required practicals🥼 🔭 Flashcards
Describe the required practical, of how to investigate the I-V characteristics, of circuit components. 🔋
Hint: resistor
1) [set up a circuit of: a battery connected by wires, to a resistor; the resistor is in so series with an ammeter and a variable resistor.
2) a voltmeter is also in parallel, across the resistor.]
3) use the voltmeter to read the potential difference, across the resistor
4) and then use the ammeter, to read the current through the resistor.
5) then record these values in a table.
6) adjust the variable resistor, recording the new readings on the voltmeter and ammeter.
7) do this several times, to get a range of readings.
8) switch the direction of the battery- meaning the direction of the potential difference, has now reversed.
9) and because of this, the voltmeter and ammeter should have negative values.
10) contuine to take several readings of potential difference, and current.,
11) then plot a graph, of the current against potential difference.
Describe the I-V characteristics of an ohmic conductor. [resistor at constant temperature]
- the current through a resistor, is directly proportional to the potential difference.
- ; if we switch the direction of the battery, and change the direction of potential difference, a straight line will still go through the zero.
What happens if a resistor gets hot ?
- If the resistor gets hot, the graph will not have a straight line through the zero- therefore don’t leave the circuit in for too long.
Describe how to prepare the circuit of an I-V characteristic, for a resistor. [ohmic conductor]
Hint: resistor
1) [set up a circuit of: a battery connected by wires, to a resistor; the resistor is in so series with an ammeter and a variable resistor.
2) a voltmeter is also in parallel, across the resistor.]
Describe the required practical, of how to investigate the I-V characteristics, of circuit components. 💡
Hint: set up a circuit, parallel, read the, current, record, adjust, battery, contuine, plot
1) [set up a circuit of: a battery connected by wires, to a filament lamp; the filament lamp is in so series with an ammeter and a variable resistor.
2) a voltmeter is also in parallel, across the filament bulb.]
3) use the voltmeter to read the potential difference, across the filament bulb
4) and then use the ammeter, to read the current through the filament bulb
5) then record these values in a table.
6) adjust the variable resistor, recording the new readings on the voltmeter and ammeter.
7) do this several times, to get a range of readings- with the battery in the forward and reverse direction.
8) contuine to take several readings of potential difference, and current.
9) then plot a graph, of the current against potential difference.
Describe the I-V characteristics graph of a filament bulb 💡
- the current isn’t proportional to the potential difference- since when the current increases—> the temperature of the filament lamp increases.
- the increased temperature causes the resistance to increase.
What else can you tell me about the I-V characteristics graph of a filament bulb?💡
Hint: less current, curve
- as the resistance increases, less current flows per a unit of potential difference.
- this means the graph gets shallower [hence the curve]
In a filament bulb, what happens of the direction of the potential difference is changed ?
- [; if the direction of potential difference is changed, it will still have the same shape]
Describe how to prepare a circuit of an I-V characteristic, for a filament lamp. 💡
1) [set up a circuit of: a battery connected by wires, to a filament lamp; the filament lamp is in so series with an ammeter and a variable resistor.
2) a voltmeter is also in parallel, across the resistor.]
Describe the required practical, of how to investigate the I-V characteristics, of circuit components. 🔦
Hint: diode
1) [set up a circuit of: a battery connected by wires, to a diode; the diode is in series with an milliammeter and a variable resistor.
2) a voltmeter is also in parallel, across the diode.]
3) additionally, there is an extra resistor- as diodes are easily damaged by a high current- the extra resistor, will keeps the current relatively low, and protect the diode.
4) use the voltmeter to read the potential difference, across the filament bulb and then use the ammeterto read the current through the filament bulb
5) then record these values in a table.
6) adjust the variable resistor, [a number of times] recording the new readings on the voltmeter and ammeter- do this with battery in the forward and reverse direction.
8) contuine to take several readings of potential difference, and current.
9) then plot a graph, of the current against potential difference.
Why is an milliammeter in a circuit, that has a diode in ?
- the current will be low, so a very sensitive ammeter needs to be used- known as a milliammeter
Why is an extra resistor used in a circuit, that has a diode in ?
- additionally, there is an extra resistor- as diodes are easily damaged by a high current.
- the extra resistor, will keeps the current relatively low, and protect the diode.
Describe the I-V characteristics for a diode ? 🔦
- there will only be a current, if the potential difference is around 0.6-0.7 volts.
- and as the potential difference increases beyond this, the current then rises sharply.
What else can you tell me about the I-V characteristics [graph] for a diode ? 🔦
- ; if the potential difference is reversed, there is no current- as in the reverse direction, a diode has a high resistance.
- in a diode, current only flows in one direction.
Describe the set up of a circuit, with a diode 🔦
1) [set up a circuit of: a battery connected by wires, to a diode; the diode is in series with an milliammeter and a variable resistor.
2) a voltmeter is also in parallel, across the diode.]
3) additionally, there is an extra resistor- [as diodes are easily damaged by a high current]
