# electronics Definition and Topics - 159 Discussions

Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active devices to control electron flow by amplification and rectification, which distinguishes it from classical electrical engineering which uses passive effects such as resistance, capacitance and inductance to control current flow.
Electronics has had a major effect on the development of modern society.
The identification of the electron in 1897, along with the subsequent invention of the vacuum tube which could amplify and rectify small electrical signals, inaugurated the field of electronics and the electron age. This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device. Until 1950, this field was called "radio technology" because its principal application was the design and theory of radio transmitters, receivers, and vacuum tubes.
The term "solid-state electronics" emerged after the first working transistor was invented by William Shockley, Walter Houser Brattain and John Bardeen at Bell Labs in 1947. The MOSFET (MOS transistor) was later invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959. The MOSFET was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses, revolutionizing the electronics industry, and playing a central role in the microelectronics revolution and Digital Revolution. The MOSFET has since become the basic element in most modern electronic equipment, and is the most widely used electronic device in the world.
Electronics is widely used in information processing, telecommunication, and signal processing. The ability of electronic devices to act as switches makes digital information-processing possible. Interconnection technologies such as circuit boards, electronics packaging technology, and other varied forms of communication infrastructure complete circuit functionality and transform the mixed electronic components into a regular working system, called an electronic system; examples are computers or control systems. An electronic system may be a component of another engineered system or a standalone device. As of 2019 most electronic devices use semiconductor components to perform electron control. Commonly, electronic devices contain circuitry consisting of active semiconductors supplemented with passive elements; such a circuit is described as an electronic circuit. Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes, integrated circuits, optoelectronics, and sensors, associated passive electrical components, and interconnection technologies. The nonlinear behaviour of active components and their ability to control electron flows makes amplification of weak signals possible.
The study of semiconductor devices and related technology is considered a branch of solid-state electronics.

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1. ### Measuring Capacitance using a basic Multimeter

Is there any way to measure the capacitance of a capacitor indirectly using a multimeter that does not have the option to measure capacitance directly?
2. ### Comp Sci Signal to Noise Ratio Help

So pretty confident I understand part (a) however for part (b) I'm not sure if I have carried it out correctly if someone could give me a pointer? (b) 5dBmV Input as a voltage: 5=20Log(V/1mV) V=105/10 V=1.77827941mV Then the noise level is 20dbμV so changing to a voltage: 20=20*Log(V/1μV)...
3. ### LED module failing due to DC motor?

I use a 2 Relay Motor module to control Direction on a motor (linear actuator). When Relay A is active, actuator retracts. When Relay B is active, actuator extents and Led Module is activated. After some repetitions Led module fail. Cause of the fail? I believe Surge voltage, although i am not...

[New poster has been reminded by the Mentors to show their work on schoolwork problems] I have tried many times to solve this problem, but can't understand how to get the value of Im and hence cannot find the Peak & other values of the load current. Please help me to solve...
5. ### Engineering Small signal AC modeling for a boost converter with resistive losses

I've attached my attempts at the solution and the actual question below. I believe the only issue I am having is I don't know how to get rid of "I" in both my final inductor and capacitor equations as the HW states I shouldn't have anything in term of I. I believe I need to put "I" in terms of...

7. ### The important non-fundamental electrical components?

Through my 2 analog classes and 2 electronics classes I have learned about resistors, inductors, capacitors, BJTs, Mosfets, and FETS. What are some other fundamental components that I should be taking a look at? To add to this, I dont consider gates as fundamental because they are built up from...
8. ### Engineering Sketching output waveforms while considering slew rate

1. Using the frequency equation I know the time period is 1 millisecond. 2. The duty cycle (50%) equation tells me that the pulse width and the amplitude is 1 V. 3. Thus the input waveform looks like this : (?) 4. As the slew rate is 0.5 volts per microsecond, the output voltage would take...
9. ### Engineering Basic opamp design problem ##V_{output} = 3V_1 - 2V_2##

Here I let ##R_2 = 2 ## kohms and ##R_1 = 1## kohms. Using this suggests that ##R_3 = 0## and ## R_4 = 1 ## kohms (?!) The resulting circuit is Is this the correct way to solve this? PS : I just realised that I have interchanged ##V_1## and ## V_2## in the diagram!
10. ### Are ISFETS available for cheap or am I out of luck

I was looking into measuring the ph levels of a lake nearby where I live. I wanted to tie the experiment to my electronics coursework so I did some reasearch and found the wonder electronic that is the ISFET. Unfortunately, I cannot find anywhere to buy an ISFET transistor; I can easily find...
11. ### Designing a motor control circuit to use a DC Motor to behave as torsional spring

I'm a relatively new entry into the world of electronics so my understanding of what is possible may not be an accurate one. In a nutshell, I would like to have a DC motor act as a torsional spring with some variable virtual spring constant (k). The motor, or "spring", would act against an...
12. ### How do I find the frequency, speed and direction of a wave

Hey I am trying to learn how waves move in time and I am not sure how to solve the following question. Can someone please guide me through it.
13. ### How to calculate the efficiency of a switch mode power supply?

I know how to calculate the power output and input by analyzing the current in put and output with multimeters and using the formula P=VI. But P_out is obviously incomparably smaller than P_in so the efficiency would suck this way. Is there a better way to do this??
14. ### Engineering Help finding this node voltage

I am given that all the BJTs are the same. First of all, when finding node voltages like Vref should I make the node voltage a voltage source first and then do circuit analysis? If so then I would use KVL but that does not give me Vref = 2Vbe. I do know that Vref = Vb1 = Vb2. What am I doing...
15. ### Must a load consume the entire available current or only what it needs

So if I have a source of 5V and 20 amp then the maximum power I can get from the source will be: $$P_{max} = 5*20 = 100W$$ but my load can only take in 5 watts, it will blow up. But, does this have to happen or does my load only take what current it needs? My guess is that the load takes in...
16. ### Find the Thevenin's Equivalent for the following circuits

I have actually already written out and solved for my own solutions to these problems, but I was wondering if I could get a second opinion on my solutions: For Problem 3: For Problem 4:
17. ### How can I determine whether my basic circuit will work? A battery and two light sources...

Homework Statement:: How can I determine whether my basic circuit will work? A battery and two light sources. Homework Equations:: conceptual question, use basic ohms law, current law, voltage law, etc. This is not a homework question, i am just trying to understand electronics better. I am...
18. ### How to find the current and voltage in a circuit with current sources?

Summary: Facing a circuit with 2 parallel resistors and 2 current sources (1 dependent, 1 independent). Trying to find the current, voltage, power delivered by the independent current source and power delivered by the dependent current source. I'm trying to start by finding the current i0 but...
19. ### I How do I calculate the expected Gain?

I am doing an experiment in electronics with AC RLC circuits, But there are a few things about what I need to do that I don't understand. First: While I know in the circuit diagram we include the internal resistance of the Inductor in series, but I don't know why we include it in series rather...
20. ### Engineering Calculating the gap of a parallel plate capacitor

I've been given this question for my TMA2, I've tried looking at the learning material but it gives no information on how to calculate the gap? Does anyone have a formula for this? Or can someone point me in the right direction? Thanks
21. ### PNP transistor and Voltage

The problem: My attempt:
22. ### The 555 timers I use don't always generate pulses

I have 3 555 timers. They don't always produce pulse. Sometimes They do. Sometimes they don't. Why don't they always produce pulses? I use electrolytic capacitors. There is nothing connected to the 5th pin.
23. ### Studying What's the best way to apply the concepts learned in physics 2?

I'm finishing up physics 2(intro E&M) at my college, and I'd like to apply the concepts I learned in it over the summer. I was considering working through an electronics book, or building a radio, etc. What kind of projects or books do you recommend to cement some of the topics I learned in a...
24. ### Electrical How can I waterproof an electrical component?

Good evening, it's been a while since my last thread here in PF. I will go straight to the point: I want to measure temperature using an NTC3950 thermistor. My circuit diagram is as follows: It's basically a voltage divider. By varying the temperature acting upon the thermistor the output...
25. ### I Why high Q factors have low phase noise

If we define Q factor as 2*pi* energy stored/ energy dissipated per cycle, what's the physical insight behind obtaining low phase noise for oscillators when we have high Q factors? (I know the mathematical derivation based on finding the frequency profile of an oscillator (like LC oscillator)...
26. ### B The Gain of the Inverting Amplifier and Virtual Earth...

This is an inverting amplifier incorporating an ideal op-amp with infinite open loop gain. I have a simple question concerning the derivation of its gain (-R2/R1). The point I circled is at 0V (Virtual Earth) but then, if V+=V-, Shouldn't Vout=0 regardless of what R2 and R1 are?? What's wrong in...
27. ### Temperature of a thin bulb filament

In my assignment question, the length L and radius r is given and asked to find out how the Temperature of a thin bulb filament which depends on those two parameters. and the answer is r^(1/4)*L^(-1/2). I cant figure out how. Which relation is involved?
28. ### How is the Aging of Electronic Equipment determined?

I am working in telecom company and they told me that they installed new system and then they told me the equipment will be EOS (End of Service) after 5 years. I was wondering that how the electronics equipment's age is calculated. If I strictly categorize my questions and explain the confusion...
29. ### Equivalent resistance with a capacitor

Homework Statement So I need to find the equivalent resistance for the following RC circuit to calculate the time constant, but I got stuck in terms of finding out the equivalent resistance. Homework Equations V = IR The Attempt at a Solution So the thing im not sure on is how do you...
30. ### Reading datasheets to pick a comparator

Hello, I've got a voltage comparator, well only on schematics, I need to chose one and I need some help interpreting datasheet. The datasheet I was looking at is of a lm393. My input voltage ranges from -7.8V to +7.8V. The datasheet says -0.3 to something. So it's not usable, right? I was also...