Search results
Results from the WOW.Com Content Network
The input resistance of the load stands in series with Rs. Whereas the voltage source by itself was an open circuit, adding the load makes a closed circuit and allows charge to flow. This current places a voltage drop across , so the voltage at the output terminal is no longer .
The load line diagram at right is for a resistive load in a common emitter circuit. The load line shows how the collector load resistor (R L) constrains the circuit voltage and current. The diagram also plots the transistor's collector current I C versus collector voltage V CE for different values of base current I base.
Electric current can be directly measured with a galvanometer, but this method involves breaking the electrical circuit, which is sometimes inconvenient. Current can also be measured without breaking the circuit by detecting the magnetic field associated with the current. Devices, at the circuit level, use various techniques to measure current:
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
Angle notation can easily describe leading and lagging current: . [1] In this equation, the value of theta is the important factor for leading and lagging current. As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be ...
is the voltage at maximum load. The maximum load is the one that draws the greatest current, i.e. the lowest specified load resistance (never short circuit); is the voltage at minimum load. The minimum load is the one that draws the least current, i.e. the highest specified load resistance (possibly open circuit for some types of linear ...
Equations for time-invariant AC circuits take the same form as Ohm's law. However, the variables are generalized to complex numbers and the current and voltage waveforms are complex exponentials. [29] In this approach, a voltage or current waveform takes the form Ae st, where t is time, s is a complex parameter, and A is a complex scalar
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.