IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: gaurav95 on May 16, 2010, 01:45:16 pm
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Hi
Can somebody please explain me something
1) Can u give me some e.g.s of application of left hand rule and right hand rules.......pls i don't understand it where to use which one............?
2)In transistor IB+IC=IE So my teacher told that the IC current is amplified how is that???
3)IN diodes what is full wave/half wave rectifiacation.....why and where and when its used......................??
4)what is potential divider,and time delay circuit...............??
I have asked too many doubts.......... Thanks a lot............
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Fleming's Left-Hand Rule is used when dealing with motors. It shows the direction of the thrust on a conductor carrying a current in a magnetic field. It can be recalled by remembering that "motors drive on the left, in Britain anyway".
The Right-Hand rule is used when dealing with generators. It shows the direction of induced current flow when a conductor moves in a magnetic field. It can be recalled by remembering that the right hand is used when dealing with generators.
For both these rules:
- The Thumb represents the direction of Motion of the conductor.
- The First finger represents the direction of the Field. (north to south)
- The Second finger represents the direction of the induced or generated Current (the direction of the induced current will be the direction of conventional current; from positive to negative).
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Potential dividers
Potential dividers are used for dividing up the voltage, so that a part or parts of a circuit only receive the voltage they require. Potential dividers consist of two or more components (usually resistors) arranged in series across a power supply.
The circuit diagrams attached show three common types of potential divider: two fixed resistors in series, a fixed resistor and LDR in series, and a thermistor and variable resistor in series. (Note that the resistors are usually drawn vertically on a circuit diagram.)
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Rectification
A common use for diodes is rectification - that is, the changing of alternating current into direct current. (An alternating current (AC) is one which flows alternately in opposite directions around a circuit, while a direct current (DC) is one that always flows in one direction only).
A rectifying circuit can be found in the transformers used with many types of equipment that require a mains alternating current to be converted into a smaller direct current - eg electronic keyboards or mobile phone chargers.
The circuit diagrams attached show the two methods of rectification.
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Potential dividers
Potential dividers are used for dividing up the voltage, so that a part or parts of a circuit only receive the voltage they require. Potential dividers consist of two or more components (usually resistors) arranged in series across a power supply.
The circuit diagrams attached show three common types of potential divider: two fixed resistors in series, a fixed resistor and LDR in series, and a thermistor and variable resistor in series. (Note that the resistors are usually drawn vertically on a circuit diagram.)
awsome tips ! + rep ! this was good revision for me + the left hand remembring thing was funny :P adn useful cheers
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:)
Glad I could help. Thanks!
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Hi
Can somebody please explain me something
1) Can u give me some e.g.s of application of left hand rule and right hand rules.......pls i don't understand it where to use which one............?
2)In transistor IB+IC=IE So my teacher told that the IC current is amplified how is that???
3)IN diodes what is full wave/half wave rectifiacation.....why and where and when its used......................??
4)what is potential divider,and time delay circuit...............??
I have asked too many doubts.......... Thanks a lot............
2. (http://www.kpsec.freeuk.com/images/transbce.gif)
IE and IC are connected to the same circuit, the small current from IB can be used to control the larger circuit, that is the circuit which goes through IE and IC, the sum of the current flowing through that larger circuit would be the output at IE, that is IB + IC. Notice that you are amplifying the very small current, that is, IB in this case ... The transistor can also be used as a switch to turn on a low-power electrical component, such as a logic gate.
4. A capacitor can be found in a time delay circuit. It is a component that charges up when a current flows through, the current stored can be used to power another device. As it takes time for the capacitor to charge up, the arrangement is hence called a time delay curcuit.
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Thanks a lot to both of you +reps
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Thanks! :)