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1. DC diodes 2. Rectifier 3. DC power supplies 4. Bipolar junction
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You are currently reading a thread in /g/ - Technology

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1. DC diodes
2. Rectifier
3. DC power supplies
4. Bipolar junction transistor
5. Bipolar junction transistor switch
6 Bipolar junction transistor biasing
7. Common Emitter Amplifiers
8. Common Collector Power Amplifiers
9. Field Effect Transistors
10. Operational Amplifiers

ALL THESE ARE BEING TESTED IN TWO DAYS.

/g/ I think im fucked, i need to get 90 to pass. Quiz me on these, ask me questions so i can test myself
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>>52664027
Sorry I don't know what the hell any of that is. Move along.
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>>52664027
Why do I get shitty sound with an LM358 OpAmp in my headphone amplifier while the sound with that more expensive OPA2132 one is better?
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>>52664027
/g/ is for technology, not whatever this crap is.
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>>52664027
Why even use BJTs if FETs don't need current to be driven and don't waste energy this way?
Which is a good replacement FET for something like a 2n222 which can be used pretty much everywhere?
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>>52664065
Because its more expensive :^)
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>>52664065
perhaps the price does provide you a bit more "performance?"

>>52664115
this

>>52664097
> /g/
> technology
> ITT: transistors
> mfw every bright rectangles you use are made of transistors

>>52664114
bjt was made in 1940 or something, and bell made fets later...
1. FET shows poor performance at high frequency
2. FET has small gain-bandwidth compared to BJT
3. FET shows poor voltage gain
4. FET can be operated only in low power applications
>>
>>52664163
> perhaps the price does provide you a bit more "performance?"
No, it's because these standard OpAmps can't provide much current at the output.

>1. FET shows poor performance at high frequency
If I'm not totally wrong the transistors inside CPUs are also FETs. 4GHz = not a high frequency?
>2. FET has small gain-bandwidth compared to BJT
>3. FET shows poor voltage gain
>4. FET can be operated only in low power applications
Why are there FETs on my Multicopter's ESCs? (40A each)
Why are there FET's in Power Supplies with hundreds of watts?
>>
>>52664221
bro u r going wayyyy too deep
im only learning the basics, not actual modern technological electronics and its inner wrokings
>>
DC diodes cover AC to DC by almost infinitely blocking one direction and almost infinitely letting the current through the other, causing the current not to alternate, but to be direct
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>>52664027
>1. DC diodes
What is a DC diode? Is there also a AC diode?
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>>52664041
>>52664097
This is the level of /g/ everybody. Take note of these fine gentlemen!

OP: post this on /diy/ instead or ask around in the /ohm/ general.

Also, unless this is a complete noob to analog electronics tier test there is no way to learn all that in two days. Learn enough to pass, fuck the rest.

And what is 90? 90/100? 90/9000?
>>
Install Gentoo
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>>52664381
90% in test

i got the basics. it's just little details that is bit too much like, "input impedance of a typical common collector amplifier is lower than common emitter with unbypassed, and about the same as common emmitter when bypassed"

also how do you find custom boards? i assume /ohm/ is custom???
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>>52664346
I don't think an AC diode exists, If so it would be called an invertor
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>>52664346
from what we are learning there is no DC diodes. However when you set up the circuits with transistors (which is basically couple of DC diodes in pair) you can do DC analysis and AC analysis and see the amplifications.

pretty much speakers and stuff you know
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>>52664381
I would just read a book, then look at with example test questions and their solutions and then try to solve old tests on my own instead of wasting time on 4chan.
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>>52664065
>why does an op-amp that's better in every aspect provide better sound?

Compare the two, you dingus:

>LM358
http://www.ti.com/product/LM358-N
>OPA2132
http://www.ti.com/lit/ds/symlink/opa2132.pdf

8 times the bandwidth with significantly less noise.
>>
>>52664419
this
>>
Analog electronics is deprecated. Learn embedded systems, microcontrollers & C.
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>>52664417
>also how do you find custom boards? i assume /ohm/ is custom???
It's a thread on /diy/, not a board. Like there are threads as /tpg/ - ThinkPad General here on /g/. So go to /diy/ and type "ohm" in the search bar.
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>>52664452
you think i want to learn this :P
i cant wait for propulsion systems
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>>52664465
gotcha
was confused for a sec
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>>52664417
Go to /diy/, there's a general there called /ohm/.. kind of like /dpt/ is here only it's for electronics..

>>52664434
This. Go to a library, sit your ass down at the relevant section and read, read, read. When they close, take the books with you and read some more. Learning from the Internet is the shittiest way to do anything.

>>52664452
Can you please go be retarded somewhere else?
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>>52664452
You still need the DC power supply to drive all that stuff.
But off course, nobody wants to build a analog computer with OpAmps anymore.
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>>52664221

>the transistors inside CPUs are also FETs. 4GHz = not a high frequency?
CPU's are digital electronics, the FET's are used for switching electronics signals. High frequency in the scope of analog electronics tends to mean RF/microwave stuff, and you get some tradeoffs between BJTs versus FETs.
>>2. FET has small gain-bandwidth compared to BJT
>>3. FET shows poor voltage gain
>>4. FET can be operated only in low power applications
>Why are there FETs on my Multicopter's ESCs? (40A each)
>Why are there FET's in Power Supplies with hundreds of watts?

Those are most likely power MOSFETs, and are specifically designed to handle large currents. The points which he's said about FET are true in general.

>>52664452
>digital ic designers losing jobs to outsourcing/job cuts
>mixed-signal ic designers still raking in mad $$$

RF still exists, and is still alive and well with all the retards snapping up a new phone every year.
>>
>>52664114
>Driving motors with voltage
>Driving audio with voltage

BJT's and FET's are for different things. One amplifies voltage and one for current. That's extremely simplistic, but that's one way to think of it.
>>
>DC diodes
Kinda redundant I think. Diodes block current in one direction and allow current in another. A diode is also known as a PN junction because it's made up of 1 layer of P type silicon and 1 layer of N type silicon. They're a one way valve of sorts

>Rectifier
A device that takes AC and turns it into DC. A single diode is considered a rectifier but it can only take half of an AC waveform so it's a "half wave rectifier". Four diodes arranged in a certain way can create a full wave rectifier for better efficiency.

>DC power supplies
A linear power supply is just one or more diodes and a smoothing capacitor. A regulated power supply is one that has a voltage regulator on the output stage to keep the voltage constant. I'm not going to try and describe a switched mode power supply because I'm not an electrical engineer, too fucking complicated.

>Bipolar junction transistor
A BJT is arranged in a similar way to a diode but it has a third layer of either N type or P type silicon. They come in one of two varieties PNPs or NPNs and they can function as a switch. Current that goes through the "base" causes current to flow from the collector to to emitter or vice-versa depending on the type.
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>>52664610
very general... only problem im having is on getting the minute details
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>>52664452
lol

This guy knows nothing, Don't listen to him. If you want proof, play a song, or take out your cell phone.
>>
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>all these retarded replies

OP just go to /ohm/ and remember /g/ is just for shilling and circlejerking over stupid things
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>>52664652
What minute details? Do you need to know how an op-amp works? Amplifier topologies? We don't know what your test is going to be like.
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>>52664652
You're probably better off studying whatever material you have. You should direct these things to /diy/ they're somewhat more knowledgeable about electronics than /g/ is. It's a slow board though.
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>>52664592
>>Driving motors with voltage
Pretty much every brushless motor is driven by FETs.
>>Driving audio with voltage
The OpAmps for audio amplifiers are also driven by voltage, there is (almost) no current flowing inside the inputs of an OpAmp.

>BJT's and FET's are for different things. One amplifies voltage and one for current. That's extremely simplistic, but that's one way to think of it.
I know that, but most of the hobby stuff I see still uses BJTs for switching stuff (not amplifying some fancy hf signals or analog circuits). Is there no standard TO92 FET that's cheap and suitable for the usual voltages <30V up to 1amp that's very common like 2n222s are for BJTs?
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>>52664163
>1. FET shows poor performance at high frequency
in terms of what? gain?... in high frequency applications you use staged amplifiers because FET are really good at switching and combined with high input impedance, they make a great amplifier, expensive in parts per amp, but really good.
>2. FET has small gain-bandwidth compared to BJT
as above, staged amplifiers... FETs are used to generate low gains but they can be chained to another circuit that has better gain response to avoid messing with the input signal
>3. FET shows poor voltage gain
as above... you get the idea
>4. FET can be operated only in low power applications
which is EXTREMELY great for low power applications and digital electronics... remember, less power = less heat = less failing electronics
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>>52664678
what is the advantage of multi stage audio amp

like this
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Lab on higher order Butterworth filters tomorrow. I know how you feel bruh
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>>52664702
>Pretty much every brushless motor is driven by FETs.

That's more out of necessity than anything, I don't think you'll find a BJT handling multiple amps with a current gain that would allow an MCU to control it with its ~40mA of current capacity.

>>52664822
>OP talking about FETs
>argue that staged amplifiers exist that use FETs in addition to BJTs

I think you missed the point mate.
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>>52664027
what's the difference between the anode and the cathode?
how do you make a rectifier?
what does the grid in a triode tube do?
i don't even remember these things myself but i went to school for it once...
>>
Guys legit question here. OPAMP has a very high gain. So if the input is 1V it outputs thousands of volts. Why can't that voltage be used to power the whole fucking house or some heavy equipment?

I asked to my professor but she laughed. Am I retarded?
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>>52664027
For each of these components, decribe a test method you would use to check if they have failed or not
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>>52666312
Conservation of energy. The output cannot be more than the input no matter how high the gain.
Yes, you are definitely retarded.
And a troll.
>>
>>52664027
i get shit like this in a few days too.
The problem is that i get circuits with like 2-3 operatorional amplifiers and other elements and i cant find a good source on were to learn.
>>
>>52664027
>DC diodes
There are AC diodes?
>>
>>52666312
because the opamp has two power lines coming into one of +15v and the other -15v which it uses to output the correct power. if the input voltage difference generate an output higher than this it will cut off i.e. you just +/15v at the no matter how high you make it.

secondly the output power is limited by how much you can input so your power supply has 15v/1A output limits you won't be able to exceed 15watts out put power.

finally, you really should know this if you're going in to an exam testing stuff like this. it's really basic stuff.
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>>52664027
Explain the Hall Effect as if I were a five year old.
>>
>>52664163
>bjt was made in 1940 or something, and bell made fets later...
Actually the patent for a FET was filed in 1925.
Also BJTs are garbage, enjoy your double breakdown voltage :^)
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>>52666874
>BJTs are garbage
literally this, no excuse to use them over FETs
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>>52664097
This is real technology you faggot. Now go back to your animu desktop containtment thread.
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>>52664930
>That's more out of necessity than anything, I don't think you'll find a BJT handling multiple amps with a current gain that would allow an MCU to control it with its ~40mA of current capacity.
No, you moron, its because you can easily archive >95% effiency with FETs, while BJTs have way more losses by design. Also no retard will control his transistors directly from an MCU, because simply wont work. You always need an additional driver chip
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>>52666873
Oh my god, where are your parents
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>>52666698
Thanks for the point. Not a troll though.

>>52666855
Thanks for really convincing answer. Nice dubs too.

You guys are awesome.
>>
>>52664027
What is open-loop gain of an opamp?
What is the closed-loop gain of an opamp?
How are the two related?
Describe how the inverting and the non-inverting amplification circuit works?
Thread replies: 53
Thread images: 4

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