Measuring Equipment

Measuring Equipment

The electronic measuring equipment used to create stimuli and measure the performance of the devices under test (DUT for its acronym in English) .The measurement of mechanical quantities, thermal, electrical and chemical is performed using devices called sensors and transducers. The sensor is sensitive to changes in the measured variable, as a temperature, a position or a chemical concentration. The transducer converts these measurements into electrical signals, which can feed reading instruments, recording or control of the measured quantities. Sensors and transducers can operate at locations remote from the observer, as well as inadequate or impractical for humans environments.

Some devices simultaneously act as a sensor and transducer. A thermocouple consists of two joints of dissimilar metals that generate a small voltage that depends on the differential between the junctions term. The thermistor is a special resistor, whose resistance value varies with temperature. A variable resistor can convert the mechanical movement into an electrical signal. Distance measuring specially designed capacitors are used to detect light and photocell are used. To measure speed, acceleration or liquid flows are used to other devices. In most cases, the electrical signal is weak and must be amplified by an electronic circuit. Below is a list of the most important measurement is presented:

• Galvanometer: measures the change of a certain magnitude, as the intensity of current or voltage (or voltage). It is used in building analog ammeters and voltmeters.

• Ammeter and current clamp: measure the electric current.

• Ohmmeter or Wheatstone bridge: measure electrical resistance. When the electrical resistance is very high (about 1 M-ohm) or megger insulation tester is used.

• Voltmeter: measures the voltage.

• Multimeter or multimeter: measure the three magnitudes mentioned above, plus electrical continuity and the B value of the transistors (both PNP and NPN).

• Power meter: measures electrical power. It consists of an ammeter and a voltmeter. Depending on the connection settings can deliver different measurements of electrical power, as the active power and reactive power.

• Oscilloscope: measure change of current and voltage versus time.

• Logic Analyzer: test digital circuits.

• Spectrum analyzer: measures the spectral energy of the signals.

• Vector signal analyzer: as the spectrum analyzer but with digital demodulation functions.

• Electrometer: measures the electrical charge.

• Frequency or frequency: counter measures the frequency.

• Time-domain reflectometer (TDR): test the integrity of long cables.

• Capacitance meter: measures electrical capacity or capacitance.

• Electric meter: measures electrical energy. Like the power meter can be configured to measure active energy (consumed) or reactive energy.

Read More

Electronic Circuits

Electronic Circuits

A circuit is a mains (interconnection of two or more components, such as resistors, inductors, capacitors, power switches and semiconductor) that contains at least one closed path. A linear circuit, consisting of sources, linear components (resistors, capacitors, inductors) and linear distribution elements (transmission lines or cables), has the property of linear superposition. They are also easier to analyze, using methods in the frequency domain, to determine their response to direct current into alternating current and transient.

A resistive circuit is a circuit that contains only resistors and voltage and current sources. Analysis of resistive circuits is less complicated than the analysis of circuits containing capacitors and inductors. If sources are direct current, it is called direct current circuit.

A circuit board having electronic components is called an electronic circuit. These networks are generally nonlinear and designs and tools require more complex analysis.

components

• Component: A device with two or more terminals where a load can flow inside. In Figure 1 are nine components between resistors and sources.

• Node: Point a circuit where more than two drivers concur. A, B, C, D, E are nodes. Note that C is not considered as a new node, since it can be considered as the same node A as including no potential difference or voltage have 0 (VA - VC = 0).

• Rama: Set of all branches of between two consecutive nodes. In Figure 1, seven branches are: the source AB, BC by R1, AD, AE, BD, BE, DE. Obviously, for a branch can only drive a current.

• Mesh: Any closed path in an electrical circuit.

• Source: The component that is responsible for transforming some energy into electrical energy. In the circuit of Figure 1 there are three sources of current, I, and two voltage, E1 and E2.

• Conductor: Commonly called wire; It is a negligible resistance wire (ideally zero) connecting the elements to form the circuit.

Fundamental Laws

There are fundamental laws that govern any electrical circuit. These are:

Kirchhoff's current law: The sum of the currents entering through a node must equal the sum of the currents leaving by that node.

Law Kirchhoff stress: The sum of the voltages in a loop must be 0.

Ohm's law: Voltage on resistance equals the product of the value of said resistance by the current flowing through it.

Norton's Theorem: Any network that has a source of voltage or current, and at least one resistor is equivalent to an ideal current source in parallel with a resistor.

Thevenin theorem: Any network that has a source of voltage or current, and at least one resistor is equivalent to an ideal voltage source in series with a resistor.

Superposition theorem: In a grid with several independent sources, the response of a particular industry when all sources are active simultaneously is equal to the linear sum of the individual responses taking an independent source at a time.

If the circuit is not linear and reactive components may be required other more complex laws. In applying these laws or theorems a system of linear equations that can be solved manually or by computer will occur.

Read More

Resistance

Resistance

It is the physical property by which all materials tend to resist the flow of current. The unit of this parameter is the ohm (Ω). Not to be confused with the resistor component. Conversely property is electrical conductance.

Read More

Electric Current

Also called intensity, is the flow of electrons through a conductor or semiconductor in a sense. The unit of measurement of this parameter is the ampere (A). As there are continuous or alternating voltages, currents can also be direct or alternating, depending on the voltage used to generate these current flows.

Read More

Tension

Tension

It is the potential difference generated between the ends of a component or electrical device. We can also say that energy is able to set in motion the free electrons in a conductor or semiconductor. The unit of this parameter is the volt (V). There are two types of stress: the continuous and alternating.

• DC voltage (VDC) It's one that has a definite polarity as that provided by batteries and power supplies.

• AC voltage (VAC) It's one whose polarity is changing or alternating over time. The most common sources are alternating voltage generators and domestic energy networks.

Read More

Electronic Signals

Electronic Signals

It is the representation of a material physical phenomenon or state through an established relationship; the inputs and outputs of an electronic system will be variable signals.

In electronics working with variables that take the form of voltage or current commonly these can be called signals. Primarily signals can be of two types:

• Variable analog-they are those that can take an infinite number of values ​​between two limits. Most real-life phenomena show signs of this type (pressure, temperature, etc.).

• Variable digitally also called discrete variables, meaning these, the variables that can take a finite number of values. Be easily performed by the physical components with two different states is the number of values ​​used for such variables, which therefore are binary. Being easier to deal with these variables (in logic would be the V and F values) are generally used to link several variables to each other and to their previous states.

Read More

Components

Components

For the synthesis of electronic circuits electronic components and electronic instruments are used. Below is a list of the most important instruments and components in electronics, followed by their most common use is as follows:

• Speaker: sound reproduction.
• Cable: conduction of electricity.
• Switch: reroute an input to an output chosen between two or more.
• Switch: open or closed circuit manually.
• Battery: power generator.
• Transducer: transformation of a physical quantity into an electrical.
• Display: shows data or images.

(Examples) Analog Devices

• Operational amplifier: amplification, control and conversion of signal switching.
• Capacitor: energy storage, filtering, impedance adaptation.
• Diode: rectification signal, regulation, voltage multiplier.
• Zener diode: regulation of tension.
• Inductor: impedance matching.
• Potentiometer: variation in electrical current or voltage.
• Relay: opening or closing of circuits using control signals.
• Resistor or resistance: current or voltage division, current limiting.
• Transistor: amplification, switching.

Digital devices

• Bistable: sequential control systems.
• Memory: digital data storage.
• Microcontroller: digital control systems.
• Gate: combinational control systems.

Power devices

• DIAC: power control.
• Fuse: protection against over-currents.
• Thyristor: semiconductor switch for power control.
• Transformer: raise or lower voltage, current, and apparent impedance.
• Silicon controlled rectifier (SCR).
• Triac: power control.
• Varistor: protection against over voltage.

Read More