The transistor is a semiconductor device that can amplify signals and switch power. Most used types are bipolar (BJT, for Bipolar Junction Transistor) and MOSFET (FET, for Field Effect Transistor)

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Can someone help med with explaining a circuit? [on hold]

How can i explain this circuit to my teacher under a Presentation?
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How do we know transconductance and diffusion resistance in this question?

I know the formulas of gm and rπ, however, VT is not given. So, knowing these values R1= 51.2kΩ, R2=9.6kΩ, RC= 2kΩ, RE=0.4kΩ, ICQ = 1.81mA, VBE = 0.7V and β= 100 can we find gm and rπ because in the ...
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2answers
38 views

What are the limitations of using a LDR sensor?

I have to explain limitations for a photoresistor/LDR . I've read the book, and searched online but find nothing. Can I get help with this ? Are things that the sensor can NOT do, which other tools ...
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1answer
70 views

Calculate Base Resistor in a NPN transistor switch

I am building a switch for a buzzer that will charge up a capacitor and sound the buzzer as they hold the button down. When they release the button the buzzer will fade away as the capacitor ...
1
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2answers
458 views

PNP Transistor getting damaged frequently

I am working on below schematic: +42VA is 42 V DC and +42VAO is also 42V DC when PNP Transistor Q1 is ON. When Q1 is ON, load on +42VAO is 10 mA max. OPTO used is P181. But it is observed that Q1 ...
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1answer
67 views

TIP120 Vs. a Big Battery

I have a big battery (11.1V, 10c, 1300mAh), a load of about 0.319 Ohms, and a TIP120 transistor. Now I've heard about the wonders of the TIP120 before (and complaints too) on various Arduino forums. ...
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2answers
44 views

Idealized characteristic of power transistors

The idealized BJT characteristic it's represented as: Meaning that the transistor is able to conduct current from + to - when is turned on, and when is off it will block positive voltages. I found ...
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51 views

Class A Audio Amplifier? [on hold]

Hi all, So for my senior project, we have to design an audio amplifier, We have these small 3 watt speakers and decided to choose the 2N222 NPN BJT as our transistor. There will be an input of 5 ...
2
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1answer
248 views

Working with peak current of mosfet

In the datasheet, the transistor has two max current values, in the case of the IRF510 Continuous Drain Current = 5.6A Pulsed Drain Current a IDM = 20A with a ...
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0answers
20 views

VLSI and Carry save adder (CSA) and multiple operand addition?

I read this PPT on page 146 we have this figure: as Better to have the same sum and carry delays (both contribute to critical path) in Carry save adder (CSA) and multiple operand addition. ...
4
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2answers
97 views

Why does a C4467 transistor turn off slowly when collector-emitter current is low

I built the following circuit simulate this circuit – Schematic created using CircuitLab The clock has an amplitude of approx. 5 VDC. It's provided by a 555. I used two different values ...
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33 views

Can an IR transistor switch on a high speed object? [on hold]

I am experimenting with different means of capturing motion. Would an IR transistor opposite an IR LED, be capable of switching in observance of some object moving upwards of 1500ft/sec? If this is ...
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67 views

Small signal gain of a pnp and npn transistor circuit

Can anyone help me solve this problem as I am unable to get the small signal gain Vo/Vi of this circuit. I got the quiescent collector current of pnp and npn as 1mA. For the small signal analysis I ...
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0answers
27 views

L200 with NPN pass transistor help!

L200 datasheet: http://www.zen22142.zen.co.uk/Circuits/Power/l200.pdf In figure 24: There are two transistors, one BDW51 and one BC108. I was wondering what is the use of the second transistor ...
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1answer
63 views

555 and transistors: using a transistor to ground the reset pin of a 555 and how to drive a MOSFET with a 555

Parachute Deployment Timer I am busy trying to build a parachute deployment timer for an amateur rocket using 555 ics What have I done thus far I have a switch that closes temporarily while the ...
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25 views

semiconductor device modeling [closed]

in FDSOI NMOS,the channel is to be made of metallic conductor .since the process of accumulation,depletion and inversion need not nescessarily to take place.whether this will eliminate the threshold ...
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1answer
94 views

Voltage divider not working

I have been experimenting on transistors recently with this simulation , it works as expected and all make sense except the V1 value. In the schematics below I ...
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1answer
53 views

Voltage on a disconnected part of the circuit?

Here's an RTL NAND Gate. I am trying to measure collector-emitter voltages of both transistors when both A and B are grounded. Transistor-A's collector voltage is about 3V. My multimeter reads C-E ...
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2answers
52 views

How to size CMOS transistors

I am new to CMOS technology and I am trying to learn about CMOS logic gates. I have a problem with transistors sizing. As far as I could understand the main idea is to obtain equal rise and fall ...
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44 views

Can anyone please explain the working of a radio transmitter

I found this circuit online: I found explanation on how a radio transmitter works in this site: http://www.dummies.com/how-to/content/radio-electronics-transmitters-and-receivers.html However, I am ...
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3answers
105 views

Please explain why this simple circuit is latching 'on', but only when a fan is attached

My son and I made a circuit using an electronics kit. It's supposed to work so that when the IR receiver receives a signal from a remote control, it turns on the motor. It does that, but I noticed ...
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3answers
60 views

Gain vs Output Impedence

I am currently trying to improve my understanding of analogue IC design and my textbook kind of brushes over this problem. It is made quite clear that a low output impedance is desired so that the ...
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2answers
114 views

How is the current through resistor same as collector current in this circuit?

My textbook says that the current through resistor will be same as the collector current when the diode shown matches with the base-emitter diode internal to the transistor. Could somebody kindly ...
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79 views

MOSFET circuit: Calculating power in a resistor

This is the problem and the second question. I know by default Power = VI, but I'm not sure which voltage to take (I'm assuming Vds). I know Vgs controls Vds. I assume the Power here is Vds x Id, ...
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22 views

Does the absolute sum of the elements of the imaginary part of the Y-matrix correspond to anything?

I have a simulation of a device with 4 ports (a double gated organic field-effect transistor), about which I also have some experimental data. I also made a simulation where I extracted the impedance ...
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1answer
65 views

How many stages of transistor amplifiers should be used in order to produce an audible output

I have constructed this amplifier as shown in the circuit diagram: simulate this circuit – Schematic created using CircuitLab I have made a few inferences: Reducing the value of ...
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55 views

How to make auto off functionality for an led lamp circuit with only transistor, capacitors, timer 555 chip?

The components I have are timer 555 chip, capacitors, and transitors. I want to create sleep functionality for a led lamp which consists of 6 leds in parallel and pnp, npn transistors. I want this ...
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2answers
77 views

Transistor Use In Oscillator Design [closed]

Need to know how to actually make the transistor 2N3055 turn on and off at a set frequency to implement its use as an Oscillator. that is the Main event that I do not know. Given this information then ...
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1answer
57 views

Carry-lookahead adder in VLSI, Static VS Dynamic?

I study one course about VLSI. in adder lecture my profesor talk about Adders. in Carry-lookahead adder first talk about static version, as follows: at next we start about dynamic version of CLA ...
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3answers
102 views

Why is BJT called as current controlled current source and FET as voltage controlled? [duplicate]

If BJT amplifies only current then why CB configuration has voltage gain but no current gain?
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4answers
142 views

What does a transistor amplify?

hi guys it’s been days i am searching and reading articles and books to find out what is the factor that a transistor amplify? which leg of transistor does provides this amplified factor? i know ...
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2answers
61 views

Will this P channel Mosfet switch work from a 3v3 GPIO

I'm designing a circuit that I can reuse over again to switch loads of different kinds from around 8-30v and from around 0.5-15amp. Like a universal Solid state relay but I want my own custom circuit ...
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1answer
102 views

Old radio amplifier circuit explanation

could somebody explain me how does this audio amplifier circuit from old radio is working ? I understand role of last transistors 413,417 and 415,419 but what is the point of T409 and T411 and other ...
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1answer
82 views

what is the use of a resistor in the PNP transistor?

The R3 is connected to the output of the PIC, I could understand the NPN transistor but PNP was a bit confusing. When the transistor starts to conduct, some current will flow towards the base. My ...
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2answers
92 views

Why do we use pull up resistor with PIC?

I tried to find an appropriate answer for the question but couldn't find what I needed exactly. I found out that "Initially the output from the PIC is floating and we use the pull up resistor R7 to ...
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20 views

Building a battery powered flood sensor

I'm trying to design a device to trigger an email when water is detected on a sensor (i.e. a flood sensor for a laundry or similar). For the sensor, I'm considering a couple of electrodes/contacts ...
0
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2answers
59 views

Switch to make MCU pin float [closed]

I have an application where I need to make a ADC input pin (0-1V) float controlled by GPIO (any connect it in other cases to its input obviously). I was considering a transistor in-line with the ADC ...
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6answers
156 views

Use transistors for controlling two LEDs

I'm sure this is a pretty basic question, but I wanted to run it by you guys before creating my PCB. I want to have two LEDs on the board to indicate the global state of the board. When the board has ...
2
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1answer
142 views

what is the easiest trick to check whether a transistor is used as a switch or current amplifier?

Newbie in electronics here. I think I know the basic theory behind transistors.I would like to know based on the schematic how you can know whether the transistor is used as a switch or an amplifier ...
3
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3answers
221 views

MOSFET to run 12 V, 0.5 A door lock

After searching for a BJT solution, I decided to replace my Darlington pair with a single MOSFET transistor. I have a microcontroller with max I/O pin current of 4 mA at 3.3 V. I have a FQP30N06L ...
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2answers
71 views

How to calculate the base-current of this transistor?

Newbie in eelctronics here. How would you calculate the current trought the base of the first transistor? simulate this circuit – Schematic created using CircuitLab follow-up question: ...
3
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1answer
51 views

5v signal to switch 3.3v input

I have an arduino that has one of its inputs pulled high and 'listening' for when either of two push buttons are pressed by pulling it to ground. I would like this signal to also be sent to a nearby ...
0
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2answers
73 views

TIP120 transistor overheating with heatsink

The transistor gets really hot even though I am using a heatsink. Have I connected something wrong?
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2answers
74 views

Raspberry Pi controlled power on/off switching of an Ethernet connection

I want to power on/off an (Gigabit) Ethernet connection physically by using some circuit. The main idea was to use a transistor with the Raspberry Pi GPIO to switch an Ethernet cable. The schematics ...
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3answers
100 views

Why doesn't this transistor circuit work as expected?

This is a circuit I have designed to work as an oscillator. But it doesn't work. The way I supposed this works: When power is ON, the capacitor(C1) starts charging through 1Kohm resistor. Once it ...
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1answer
25 views

Analog circuit design(amplifier with BJT) with abstraction(model)

I tried to cascade two circuit consisting of BJT transistor : Common Emitter stage, Emitter follower. I do abstraction like belows, which means you just need to know only each unit block one by one ...
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1answer
74 views

confused about pnp transistor current flow

I am new to electronics and this question might seem silly.... see attached image please. I do not understand why in the transistor below current seems to flow from collector to emitter... because ...
3
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2answers
712 views

How does this current limiting circuit work?

A tutorial electronicsArea explains a transistor based current limiting circuit. Problem is that I am not able to understand how T1 gets switched on in the fist place. To make T1 on it needs a ...
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1answer
93 views

Why do we need a pull-up resistor when there is a floating connection at the base of a transistor?

Let's say that the base is connected to any normal PIC. My teacher was talking something like, "There will be a floating output at the base when nothing is connected so we use the R7 (10k) for ...
2
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1answer
102 views

Germanium transistors becoming noisy

Germanium transistors would sometimes become very noisy despite the in-circuit DC bias voltages testing normal. This failure was cured by replacing the offending BJT. I have found this as a teenager ...