Wednesday, July 20, 2011
Thursday, July 14, 2011
Ammeter shunts Potentiometers
Ammeter shunts An ammeter shunt is a special type of current-sensing resistor, having four terminals and a value in milliohms or even micro-ohms. Current-measuring instruments, by themselves, can usually accept only limited currents. To measure high currents, the current passes through the shunt, where the voltage drop is measured and interpreted as current. A typical shunt consists of two solid metal blocks, sometimes brass, mounted on to an insulating base. Between the blocks, and soldered or brazed to them, are one or more strips of low temperature coefficient of resistance (TCR) manganin alloy. Large bolts threaded into the blocks make the current connections, while much-smaller screws provide voltage connections. Shunts are rated by full-scale current, and often have a voltage drop of 50 mV at rated current. Such meters are adapted to the shunt full current rating by using an appropriately marked dial face; no change need be made to the other parts of the meter.s) which is relevent in the practical manufacturing of circuits using them.
Potentiometers
Main article: Potentiometer
A common element in electronic devices is a three-terminal resistor with a continuously adjustable tapping point controlled by rotation of a shaft or knob. These variable resistors are known as potentiometers when all three terminals are present, since they act as a continuously adjustable voltage divider. A common example is a volume control for a radio receiver.[13]
Accurate, high-resolution panel-mounted potentiometers (or "pots") have resistance elements typically wirewound on a helical mandrel, although some include a conductive-plastic resistance coating over the wire to improve resolution. These typically offer ten turns of their shafts to cover their full range. They are usually set with dials that include a simple turns counter and a graduated dial. Electronic analog computers used them in quantity for setting coefficients, and delayed-sweep oscilloscopes of recent decades included one on their panels.
PotentiometersMain article: Potentiometer
A common element in electronic devices is a three-terminal resistor with a continuously adjustable tapping point controlled by rotation of a shaft or knob. These variable resistors are known as potentiometers when all three terminals are present, since they act as a continuously adjustable voltage divider. A common example is a volume control for a radio receiver.[13]
Accurate, high-resolution panel-mounted potentiometers (or "pots") have resistance elements typically wirewound on a helical mandrel, although some include a conductive-plastic resistance coating over the wire to improve resolution. These typically offer ten turns of their shafts to cover their full range. They are usually set with dials that include a simple turns counter and a graduated dial. Electronic analog computers used them in quantity for setting coefficients, and delayed-sweep oscilloscopes of recent decades included one on their panels.
Capacitor
Capacitor
A device used to store charge in an electrical circuit. A capacitor functions much like a battery, but charges and discharges much more efficiently (batteries, though, can store much more charge).
A basic capacitor is made up of two conductors separated by an insulator, or dielectric. The dielectric can be made of paper, plastic, mica, ceramic, glass, a vacuum or nearly any other nonconductive material. Some capacitors are called electrolytics, meaning that their dielectric is made up of a thin layer of oxide formed on a aluminum or tantalum foil conductor.
Capacitor electron storing ability (called capacitance) is measured in Farads. One Farad is actually a huge amount of charge (6,280,000,000,000,000,000 electrons to be exact), so we usually rate capacitors in microfarads (uF = 0.000,001F) and picofarads (pF = 0.000,000,000,001F ). Capacitors are also graded by their breakdown (i.e., smoke) voltage. Capacitors rated for lower voltages are generally smaller in size and weight; you don't want to use too low a voltage rating, though, unless you enjoy replacing burnt-out capacitors in your creation.
Wednesday, July 13, 2011
Saturday, July 9, 2011
bilateral circuit unilateral circuit Linear circuits :
bilateral circuit is a circuit that behaves the same way if it is connected in the opposite direction. The term is typically used for components in electrical circuits. For example, a resistor behaves the same way no matter if it's connected left-to-right ot right-to-left. In contrast, a diode is not a bilateral component, because it conducts current in one direction, and does not conduct in the other.
unilateral circuit it is a circuit in which value of impedance or resistance of element changes with changing the direction of voltage or current.eg. circuit with diodes....
Linear circuits :
A linear circuit is an electronic circuit in which, for a sinusoidal input voltage of frequency f, any output of the circuit (the current through any component, or the voltage between any two points) is also sinusoidal with frequency f. Note that the output need not be in phase with the input.
en.wikipedia.org/wiki/Linear_circuits
It is the circuit whose parameters remain constant with change in applied voltage or current.Examples are a resistance, inductance or capacitance.
Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks wont be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.
berkeman
Feb3-09, 02:36 PM
Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks wont be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.
I prefer using the KCL method generally, and just label all the nodes and write the current sum equations for each node. Not sure what would be good tips past that... The KVL method is less intuitive for me, and doesn't feel as "physical" as the KCL method.
mplayer
Feb3-09, 09:25 PM
Some tips that might help with KCL:
-Make your reference node a node that is connected to as many voltage sources as you can to minimized the number of unknown node voltages.
-Sometimes it might be helpful to outline each node in the circuit (draw a border around the wire of each node). Makes it easier to see and keep track of the number of nodes in a circuit, for me at least.
Some tips that might help with KVL:
-I always label the mesh currents going clockwise. Whichever direction you choose to do it in, it might help to always do it the same way to minimizes potential errors.
-If there is a current source in a loop and its on the outside of that loop (not sharing it with an adjacent loop) then that is the value of that mesh current (one less equation to write
unilateral circuit it is a circuit in which value of impedance or resistance of element changes with changing the direction of voltage or current.eg. circuit with diodes....
Linear circuits :
A linear circuit is an electronic circuit in which, for a sinusoidal input voltage of frequency f, any output of the circuit (the current through any component, or the voltage between any two points) is also sinusoidal with frequency f. Note that the output need not be in phase with the input.
en.wikipedia.org/wiki/Linear_circuits
It is the circuit whose parameters remain constant with change in applied voltage or current.Examples are a resistance, inductance or capacitance.
Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks wont be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.
berkeman
Feb3-09, 02:36 PM
Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks wont be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.
I prefer using the KCL method generally, and just label all the nodes and write the current sum equations for each node. Not sure what would be good tips past that... The KVL method is less intuitive for me, and doesn't feel as "physical" as the KCL method.
mplayer
Feb3-09, 09:25 PM
Some tips that might help with KCL:
-Make your reference node a node that is connected to as many voltage sources as you can to minimized the number of unknown node voltages.
-Sometimes it might be helpful to outline each node in the circuit (draw a border around the wire of each node). Makes it easier to see and keep track of the number of nodes in a circuit, for me at least.
Some tips that might help with KVL:
-I always label the mesh currents going clockwise. Whichever direction you choose to do it in, it might help to always do it the same way to minimizes potential errors.
-If there is a current source in a loop and its on the outside of that loop (not sharing it with an adjacent loop) then that is the value of that mesh current (one less equation to write
Monday, July 4, 2011
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