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Electronics Engineering
Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.
24,372 Questions
Will the impedance in a series RL circuit increase as the frequency decreases?
When the frequency of Parallel RL Circuit Increases,XL increases which causes IL (current through inductor) decreases. Decrease in IL causes It (It=Il+Ir) to decrease,which means by relation IT=Vs/Zt ,the Zt (Total Impedance) Increases.
What is the basic function of the SCR's gate electrode?
The SCR's gate electrode is used to turn the SCR on, i.e. fire it.
What would the current flow be if a short circuit is put across the battery's terminals?
That will depend on the internal resistance of the battery.
I = E / R
Where I is the current, E is the open circuit battery voltage, and R is the internal resistance of the battery.
What is the difference between ac ups and dc ups?
DC voltage is a constant direction of current flow, it can be a constant amount or very (as long as it never changes direction it is DC). AC voltage is in the form of a sine wave (that will change direction of current flow) so at any specific instant of time you could measure a different voltage as it goes through its cycle.
What is reverse saturation current in ideal diode?
When a pn junction is reversed bias practically no current flows through it ,but a very small current flows through due to minority charge carriers ,which is known as reverse saturation current .In p type due to electrons and in n type due to holes .
Why carrier signal are sinusoidal?
It does not have to be. Voltage can be DC, sinusoidal, square wave, triangular wave, etc.
Shunts are used to bypass portions of a circuit. Shunt capacitors are frequently used to pass the high-frequency components of signals to ground. See the Wikipedia article about shunts. (Follow the web link at lower left.)
What is the rule for the total resistors when resistors are added up in series?
You add the resistances together to get the total resistance in a series circuit.
Say...
R1=10
R2=12
R3=10
R123=32
What are the two parts for a variable capacitors?
The main parts of a capacitor are:
- two conducting plates separated by
- an insulating material (called a dielectric) surrounded by
- further insulation - plastic or paper - as a protective jacket and
- external wires (connected internally to the plates) to allow the capacitor to be connected into a circuit
and, on large units:
- a protective case made of metal or plastic and
- external terminals connected internally to the plates,to allow the capacitor to be connected into a circuit.
What is the total opposition to a current flow in an AC circuit with both resistance and reactance?
Resistance
Semiconductor diodes are made from the same Silicon, and occasionally Germanium, material that transistors, integrated circuits, etc. are made from.
Diodes used in early electronic devices were made from vacuum tubes.
Somewhat later diodes were made from finned stacks of Selenium.
Simple "Crystal Radios" use Galena (lead ore) crystals with a steel pin that is manipulated to find a spot that allows electrical current to flow in only one direction.
Your description of the system is either contradictory or incomplete, therefor no answer can be given.
What is the miller effect in simple terms?
A: That becomes evident while the driving source i limited in current driving abilities the voltage increases the phenomenon occurs known as the miller effect. Once the threshold voltage is passed it begins to draw increasingly heavier drain current with respect to the gate. As the drain rises the trans conductance rises rapidly to saturation. concurrent with the rise in gain the once low feedback capacitance now swells to enormous proportions appearing as an additional to the input capacitance.
cin=ciss+[1+av]cgd
ciss= gate source in cap
cgd=m gate drain capacitance
av= voltage gain
What is the importance of transducers?
A transducer is a device that converts a physical quantity into some other type of signal eg. sound to voltage, light to current, or vice versa
What happen wen dc source and ac source conected together?
Depends if they are matched in phase and amplitude. Had a case recently where a house was miswired. There was an outlet that was connected to two breakers. I was trying to trace down a problem with a GFCI continually tripping. The clue was that as I turned off breakers one at a time, the power never went off at the input to the GFCI. When I removed the extra feed (It was in a different outlet box) the problem was fixed. It only affected the GFCI and the other things on the circuit worked. If was obviously a code violation and a bad implementation, but it "worked" in some sense.
What is the importance of chemistry in software engineering?
None, I'd suggest. Can't think of any reasonable thing.
What is the relevance of this question.
What is the purpose of the series resistor in your designed ammeter circuit?
You appear to be referring to a 'swamping resistor' which is connected in series with a moving-coil ammeter's moving coil.
To minimise any errors due to temperature changes in the resistance of the instrument's moving coil, the coil is connected in series with what is termed a 'swamping resistor' whose resistance is large in comparison with that of the moving coil, and which is manufactured from an alloy with a very lowtemperature coefficient of resistance (i.e. a metal whose resistance is hardly effected by wide variations in temperature).
For example, if the resistance of a 1-Ω moving coil increases to, say, 1.1 Ω, when its rated current flows through it, this will introduce a 10% error in the instrument's reading.
But by calibrating the instrument with a series swamp resistor of, say, 49 Ω, the overall resistance at rated current will become 50.1 Ω. This will result in an error of just 0.2%.
A swamping resistor, then, is an integral part of all moving-coil instruments and, when we refer to an instrument's 'coil resistance', we actually mean the combined resistance of the moving coil itself and its swamping resistor.
When two 4-ohm resistors are connected in parallel across 12 volts:
-- Each resistor has 12V across it, so the current is I = E/R = 12/4 = 3 amperes.
-- The total current from the battery is 6 amperes.
-- The effective resistance as seen by the battery is R = E/I = 12/6 = 2 ohms.
-- If you didn't know the voltage of the battery, you would calculate the
effective resistance of the parallel resistors in advance like this:
1/R = 1/4 + 1/4 = 1/2
R = 2 ohms.
When you connected them to a battery, the battery would agree.
Tools and materials used in drafting?
drafting instrument - tools used by draftsman to make high precision markings and technical drawings
proportional divider - looks somewhat a compass, used for equally dividing segments, also allows for scaling of measurements so they can be transferred
protractor - tool shaped in a half circle, and almost always transparent, used to measure angles or circles
triangle - also known as a set square, often used in conjunction with a protractor or compass, the triangle is used to draw 90 degree angles
T-square - Two straight edge pieces which intersect at one end, used to draw straight measured lines. Older T-squares were made of wood, whereas more modern ones tend to have clear plastic edges.
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate.
Printed circuit boards are typically made with copper. Depending on the requirements, the copper is plated to a substrate and carved away to expose the design of the board. Since there are multiple layers, they must be lined up and bonded together for a secure fit.
PCB Manufacture Process
Step 1 – The Design Before you begin manufacturing the PCB, you need to have a design of the board. These blueprints will be what you base the process off of. .
Step 2 – Print the Design
A Special printer called a plotted printer is used to print the design of the PCB. It produces a film that shows the details and layers of the board. When printed, there will be two ink colors used on the inside layer of the board:
Step 3 – Creating the Substrate Now is when the PCB will start to form. The substrate, which is the insulating material (epoxy resin and glass fiber) that holds the components on the structure.
Step 4 – Printing the Inner Layers The design is printed to a laminate, the body of the structure.
Step 5 – Ultraviolet Light Once aligned, the resist and laminate go under ultraviolet lights to harden the photoresist. The light reveals the pathways of copper. T
Step 6 – Removing Unwanted Copper Now, it is time to remove any unwanted copper that remained on the board. A chemical solution, similar to the alkaline solution, eats away at the unwanted copper.
Step 7 – Inspection The newly-cleaned layers will need to be inspected for alignment. The holes drilled earlier help align the inner and outer layers. An optical punch machine drills a pin through the holes to keep the layers lined up.
Step 8 – Laminating the Layers Now, you will see the board take shape as the layers are fused together. Metal clamps hold the layers together as the laminating process begins.
Step 9 – Pressing the Layers A mechanical press is then used to press the layers together.
Step 10 – Drilling Holes are drilled into the layers by a computer-guided drill to expose the substrate and inner panels. Any remaining copper after this step is removed.
Step 11 – Plating The board is now ready to be plated. A chemical solution fuses all of the layers together.
Step 12– Etching The same chemical solution from before removes any unwanted copper under the resist layer. The tin guard layer protects the needed copper. This step established the PCB’s connections.
Step 13 – Solder Mask Application All of the panels should be cleaned before the solder mask is applied. An epoxy is applied with the solder mask film.
Step 14 – Silkscreening Silkscreening is a vital step since this process is what prints critical information onto the board. Once applied, the PCB passes through one last coating and curing process.
Step 15 – Surface Finish The PCB is plated with either a solderable finish, depending on the requirements, which will increase the quality/bond of the solder.
Step 16– Testing Before the PCB is considered complete, a technician will perform an electrical test on the board. This will confirm the Printed Circuit Board (PCB) functions and follows the original blueprint designs.
What happened when Volta connected the parts of his cells in circuit?
An electric current flowed around the circuit.
Is it desirable for a battery to have a high internal resistance?
No, it is desirable for a battery to have a low internal resistance.
What is the effect of a short circuit on other devices in the circuit?
Electricity is designed to complete a circuit. For example, it comes into your house by way of the hot wire. Then it goes through the electrical box and through the fuse system. Finally it goes through a light bulb or some other electrical devise. Then it goes back through the neutral wire. It wants to get back to the neutral wire without doing any work. In a way, electricity acts like a river. A little stream leaves the river to run your lightbulb. However, every now and then, there is a short circuit. The circuit leading to the light bulb develops a short circuit. In that case, a lot more electricity than should tries to go through the little wire that led to the light bulb. It wants to get to the neutral wire. It is like a river overflowing through a little stream and creating a flood. It can burn out the little wire and set the house on fire. The flood runs into a culvert which holds back the flood. The short circuit blows a fuse or throws a circuit breaker and the house does not burn down. Every now and then the main fuse box blows out and a house burns down. Every now and then a wire falls down outside and people walk close to it. The ground is full of electricity and the people are killed. So a short circuit happens when electricity completes a circuit without doing any work. It is dangerious when a fuse does not blow.
What is the proper placement of an ammeter in a circuit?
Ammeter should be inserted in the place where we need to find the current. Care must be taken while inserting ammeter such that it is in series always. For example if we need to measure the current through any device, we have to connect the ammeter in series with tht device.
What is the purpose of a potentiometer?
A potentiometer is a type of position sensor. They are used to measure displacement in any direction. Linear potentiometers linearly measure displacement and rotary potentiometers measure rotational displacement.
Also known as a Potmeter or Pot, it consists of a resistive element called the track and a sliding contact called the wiper internally where end terminals are attached to the resistive element.
They are used to accurately measure voltage and help achieve a variable voltage from a fixed-voltage source.
Common Examples of Potentiometers are:
- Measuring Position on a gaming joystick
- Controlling audio equipment using volume controls
