L7805CV datasheet and application

L7805CV is a DC regulator chip

http://www.alldatasheet.com/datasheet-pdf/pdf/22634/STMICROELECTRONICS/L7805CV.html

Simple Application of L7805CV

http://html.alldatasheet.com/html-pdf/22634/STMICROELECTRONICS/L7805CV/6499/4/L7805CV.html

Great explanation of Capacitor.

From:

irc.freenode.net

#raspberrypi

(08:48:27 PM) ShiftPlusOne: It stores and releases energy. You get a build up of electrons on one side when you apply the voltage, which charges up the circuit. When the voltage is removed it discharges. It takes time to charge/discharge so it doesn't take instantaneous changes in voltage, so high frequency signals get filtered out

(08:48:29 PM) ShiftPlusOne: to what degree depends on the capacitance value

(08:49:26 PM) ShiftPlusOne: So it acts as a filter and smoothes out the noise in that circuit (as far as I understand it)

(08:56:14 PM)plugwash:the key equation with capacitors that I wish i'd been told much earlier is I=C(dV/dt)

(08:57:35 PM) ShiftPlusOne: In AC/power circuits we often treat it as a reactance X=1/(2*pi*f*C)

(08:58:40 PM) plugwash: ShiftPlusOne, right but it's IMO important to understand the underlying equation that applies in all contexts rather than just learning a series of special cases derived from it

(08:58:52 PM) plugwash: at least I think it is

Dropout voltage

http://en.wikipedia.org/wiki/Dropout_voltage

From Wikipedia, the free encyclopedia

In electronics, the dropout voltage of a voltage regulator is the smallest possible difference between the input voltage and output voltage to remain inside the regulator's intended operating range.

For example, a regulator with 5 volt output and 2 volt dropout voltage rating will only output 5 volts if the input voltage is above 7 volts (7 volt input > 5 volt output + 2 volt dropout). If the input falls below 7 volts the output will fail to regulate to 5 volts.

Dropout voltage can be as high as 2 volts for a general purpose integrated circuit regulator (such as the 78xx series), but a low dropout regulator may have a dropout of less than 100 mV at full load.

Dropout voltage will vary depending on the load on the regulator, usually increasing under higher load, due to the internal resistance of the regulator's pass transistor and circuitry. Dropout voltage also varies with respect to temperature. Dropout voltage is usually specified over a range of loads and temperatures.

Peak Current

The maximum amount of current which an output is capable of sourcing for brief periods of time.

supply voltage rejection ratio (k_SVR)

The absolute value of the ratio of the change in one supply voltage (with all remaining supply voltages held constant) to the resulting change in input offset voltage.

NOTE 1 See the reciprocal definition under "supply voltage sensitivity".

NOTE 2 This concept is sometimes referred to as "power supply rejection ratio".

NOTE 3 The abbreviations SVRR and PSRR are often used in place of symbol k_SVR; however, symbol k_SVR is preferred.

Output impedance

http://en.wikipedia.org/wiki/Output_impedance

The output impedance, source impedance, or internal impedance of an electronic device is the opposition exhibited by its output terminals to an alternating current (AC) ofa particular frequency as a result of resistance, inductance and capacitance. It is the Thévenin equivalent impedance looking back into the output terminals.

In the case of a nonlinear device, such as a transistor, the term "output impedance" usually refers to the effect upon a small-amplitude signal, and will vary with the bias point of the transistor, that is, with the direct current (DC) and voltage applied to the device.

The small-signal impedance at DC (frequency of 0) is the same as the resistive component of the impedance and is termed output resistance.

No real device (battery, generator, amplifier) is a perfect source; each has an internal impedance, though this may have little practical effect, depending on the circuit and the load.

Depending on perspective, this impedance can be modeled as being in series with an ideal voltage source, or in parallel with an ideal current source (see: Thevenin's theorem, Norton's theorem, Series and parallel circuits). Both models are equivalent, and one may choose whichever model is most convenient for analysis.

For example, having a preamplifier with a 100-ohm output impedance means the output voltage signal appears to be in series with a 100-ohm resistor.

Quiescent current

1. 
   Quiescent Current
   The standing current that flows in a circuit when the signal is not applied. The quiescent current is usually very low or lower than when processing a signal. See also: Current.
   Found op http://www.diracdelta.co.uk/science/source/q/u/quiescent%20current/source.h
   
   
2. 
   Quiescent current
   The current which continues to be drawn from the battery when the application it powers is in standby or hibernation mode. 
   Found op http://www.mpoweruk.com/glossary.htm

Biasing

From Wikipedia, the free encyclopedia

This article is about biasing in  electronics. For other uses, see  Biasing (disambiguation).

Biasing in electronics is the method of establishing predetermined voltages or currents at various points of an electronic circuit to set an appropriate operating point. The operating point of a device, also known as bias point, quiescent point, or Q-point, is the steady-state operating condition of an active device (a transistor or vacuum tube) with no input signal applied.

http://en.wikipedia.org/wiki/Biasing

Application of L7805CV