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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Lower current through different transistors

I'm building a small PIR driven circuit, currently a simple PIR activated light, and for this I'm using an RGB LED strip as I had it lying around from another project. The diagram that follows works ...
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40 views

Vds Voltage of Nmos transistor at Lineer Region

I know the conditions for mosfet Id equations in saturation, linear or cutoff mode. For this circut, how can we find the Vds voltage when we know only values of the resistors and Vdd at linear mode? ...
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the best book to practice [on hold]

I am looking for a book that would let me practice the chapters of Principles of Measurement systems by John P Bentley. I am looking for a book that has all the contents of the this above mentioned ...
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43 views

My slayer exciter circuit is non functional

I built a miniature slayer exciter using this schematic: The transistor is an MPSA-05 from Central semi, the resistor is ~22Kohm the LED is a Vishay pure green 5mm, the coil is ~250t of 36 AWG wire ...
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3answers
384 views

Convert NO switch to NC

Please excuse what may be a simple question, I am very rusty when it comes to electronics having not looked at them at all for about 25 years! I hope someone can resolve my query. I have a circuit ...
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26 views

1.5A micro motor driver transistor/IC for micro quadcopter-arduino [on hold]

im planning to make micro quadcopter using hubsan micro motors that i ordered from ebay (CL-0720-12) together with corresponding hubsan x4 proppellers. At max voltage (3.7V), motors load current is ...
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1answer
48 views

Simple lightweight high power amplifier circuit

I'm looking for a way to amplify a 12V sinusoidal signal to drive a set of transducers at ~120V with an overall power of 100W. The quality of the output signal does not have to be good, simplicity ...
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2answers
62 views

Transistors in a logic gate

What is the highest number of transistors that can be used within a gate? Very open ended and general question, but I'm trying to gain a better understanding for digital logic. In terms of chips, I'd ...
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2answers
81 views

Why is the collector- emitter voltage (Vce) not getting biased?

This question is an extension for my previously asked question here: Why is the voltage across collector and emitter pushing itself to 0.7 volts? A colleague of mine suggested that I take a look at ...
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35 views

Which transistor should i use in making “this” laser alarm system?

I am trying to make a laser-trip alarm and this is the image of the receiver part(which buzzes when there is no laser on it). I got this from instructables and the upload said that its a low voltage ...
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1answer
48 views

What kind of transistors are prone to gate/base floatation? [closed]

What kind of transistors are prone to gate/base/etc flotation? I know for sure that n-channel MOSFETs need a resistor connected to the ground to keep the gate low to obviate chances of flotations. ...
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1answer
47 views

250Voltage discharging turnoff circuit

I'm reconditioning my hybrid battery. To do so requires multiple complete discharges which I do not have time to be around for. To avoid damaging my battery I've been attampting to design a circuit ...
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2answers
85 views

Where do these 200 mV come from?

I was analyzing a circuit and when simulating it in PSpice I came across this: Is there a way of calculating without simulation (i.e. just looking at the circuit and doing the algebra) that ...
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2answers
27 views

Could A28A transistor work for controlling Rx/Tx pin?

I want to control a robot with my arduino via RX/TX. Here is the wiring: They recommend transistor pnp 2N4403. Another guy said that a small signal, low power PNP transistor such as 2N2907A could be ...
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3answers
58 views

Integrating wireless transmitter with old door chime system

The building I live in have an old door-chime system, and I wish send a wireless signal when the door-chime is triggered. There are multiple push-buttons at different locations connected to the same ...
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0answers
76 views

What does the beta factor do here? (current mirror) [on hold]

I'm reading through a textbook reference and came across a problem I don't understand how to solve: For the circuit shown in Figure, IA = 3 mA and VCE = 5.4 V. If all transistors have the same ...
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1answer
45 views

What are suitable replacements for an sot23 transistor? marking code 1p [closed]

I was replacing some capacitors on an LG TV circuit board and I slipped and broke a 1P transistor. I have a massive array of old circuit boards but can't find one with the same code. What marking ...
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3answers
215 views

Can somebody please analyse this circuit [on hold]

Can somebody explain to me how this circuit works? i understand that it is an audio amplifier circuit and it inverts the signal, and inverts it again, but i am not sure why this is the case. also ...
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2answers
72 views

Why do we need to rectify or amplify the current/voltage? [closed]

I am a beginner in Electronics. What i read now a days in my text book is about diodes,transistors etc. They are used for some rectification and amplification etc ? I wonder why do we need to give ...
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3answers
96 views

How to overcome transistor heat in slayer exciter?

I build this circuit and it works but I have two problems. The major problem is that the transistor becomes very hot quickly. I burnt my transistor due to excessive heat. How can I get rid of the very ...
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1answer
182 views

How do these capacitors in this BJT Darkness Detection circuit work?

This circuit detects darkness and produces a beep alarm. I simulated the circuit in LTspice and verified it works, but I still don't understand how the capacitor (4.7uf & 100nf) function in the ...
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3answers
61 views

AC-DC Conversion; How Much Can I Draw?

My question is how much Amperage can I draw in DC using this kind of setup. I have a 3055 and it's rated at 15A. Is that my max draw then? Power systems aren't my thing, so I'm out of my element ...
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2answers
71 views

How to choose a bypass capacitor for a common emitter amplifier?

This site says: "To increase the gain for AC signals the emitter resistor bypass capacitor is added. This should be calculated to have a reactance equal to the emitter resistor at the lowest frequency ...
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77 views

base resistor value

simulate this circuit – Schematic created using CircuitLab I am a beginner. I want to build this inverter for my academic project. I would be obliged if I could get some help. I am ...
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2answers
69 views

Mosfet H-Bridge Design Question

I have a few questions regarding an H-Bridge design that I like. I am having a little hard time understanding some parts of it. So this is the design that I found online here. I changed the motor ...
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1answer
82 views

Why is the voltage across collector and emitter pushing itself to 0.7 volts?

I designed a single stage transistor amplifier as shown in this schematic: I constructed this on a breadboard and applied the DC bias voltage to check the biasing conditions. Prior to this, I made ...
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1answer
66 views

Audio op am for low noise high volume

I am trying to make a high quality circuit to take mp3 (stereo) signal and drive a 4 ohm speaker. I have been using the LM368 as in the picture below and this has ok quality when the volume is low but ...
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4answers
428 views

LED's flash with music

I am wanting to put have a few LED's flash with the intensity of my music. I don't need a color organ, but just want the LED's to flash in sync with the music. I am amplifying the signal with a LM368 ...
3
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1answer
77 views

Would you explain the output waveform of this FM transmitter circuit?

I build this circuit and it works. I wanted to look at the output waveform by my soundcard oscilloscope software. I would expect something like the following picture: But the output waveform was ...
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1answer
41 views

Pulse Low on High Signal

I am trying to build a circuit that disconnects the output for a brief time when power is connected. However I want the circuit to remain connected after power is removed. I can achieve the first ...
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1answer
13 views

Automatic-switching reverse (back up) caravan camera

I'm wanting to try some electronics trickery after many, many years away from it. Unfortunately many of the rules evade me but I feel like I could pick it up quickly, again. My goal for my first ...
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1answer
72 views

Transistors: Explain the key differences between SMALL and LARGE-signal analysis

I'm in an electronics class and I feel like this portion of the lecture was covered in a vague manner. I'm not really sure what the purpose of doing either a large or small signal analysis is, and ...
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3answers
127 views

Should I have had a resistor before my transistor?

I've recently started playing with an Arduino and learning about circuit's. I was trying to learn a bit about using some transistors as a switch and I think in the process I ended up ruining one of ...
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42 views

Auto-start after power off in nvidia TK1 board

I'm trying to make my Nvidia board (TK1) to boot automatically. i.e., when the power goes off and comes back again i want the board to power up automatically. I have tried the Nvidia forum and found a ...
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0answers
14 views

Transistor slows motor instead of turning it off [migrated]

I'm new to electrical engineering and am currently trying to make a motor turn on for one second, turn off for one second, and repeat. I'm using an Arduino Uno's digitalWrite feature to activate a ...
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1answer
81 views

What is the most commonly used transistor?

Just a question about transistors from a rookie. I was wondering what kind of transistor is most commonly used? Bipolar transistors? JFET? MOSFET?
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1answer
108 views

Power Transistor for TDA2030 audio amp

I am attempting to make a Stereo Power Amplifier using two TDA2030A amplifiers. I want an output of at least 25 watts per channel. The datasheet shows me that I need to add a pair of power ...
3
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3answers
154 views

What is the precise definition of forward and reverse bias for a P-N junction?

I have always thought that for a P-N junction, forward-biased simply means that \$ V_{PN} > 0 \$ and reverse biased means that \$ V_{PN} < 0 \$. However, in this article about NPN BJTs, there ...
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2answers
80 views

Voltage output of a transistor

simulate this circuit – Schematic created using CircuitLab So right now i'm really confused on the voltage output of a transistor. So my common sense tells me that the \$ I_E = I_B + I_C ...
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1answer
83 views

Finding output resistance

I am confused on how to find the output resistance of transistor amplifiers in general, but more specifically when it's a combination of different resistances. Here's an example (concrete) of the ...
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2answers
88 views

What is the effect of V(CE) to saturation?

I am following this tutorial about transistors. In the tutorial, it is stated that to be in the cutoff region, \$V_{BE}<0\$ and \$V_{BC}<0\$ must be true. The tutorial also states that however ...
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1answer
94 views

Transistor - Control current flow

simulate this circuit – Schematic created using CircuitLab I am having trouble finding how to limit the current flow from the collector to the emitter of a transistor. (Is it possible? I ...
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3answers
119 views

Does a bit in Flash memory store net charge

This is with regards to the discussion in the comments in my answer to this question with regards to the charge stored in a Flash. The way a Flash memory works is that it either stores a small charge ...
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2answers
80 views

Ultrasound transducer excitation - frequency, transistor type

I currently work on my ultrasound project. I need to excite my Olympus V305-SU-F tranducer with -100 V spike pulses. Unfortunately Olympus does not provide any kind of datasheet. I know only value of ...
2
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1answer
67 views

what is the collector gain of a transistor?

I was wondering what exactly collector gain is for npn transistors, or more specifically if there is some sort of equation for getting it, and if its value changes as you change the input ...
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2answers
136 views

Resistors for transistor led circuit

Im new to electronics and have problems with calculating the resistors needed for driving an IR LED with an transistor. My VDD is 3.3V, the LED needs 1.3V and I want to drive it close to 20mA, so I ...
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2answers
76 views

Why collector current is inwards to transistor in an NPN?

In this page, the following model is given for an NPN BJT. simulate this circuit – Schematic created using CircuitLab Also, it is stated that I(e) is outwards from the transistor, I(b) ...
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5answers
317 views

What is the function of this transistor?

There is a tutorial on multi-stage amplifiers. It doesn't explain every details. The first stage is the typical amplifier with stable bias, and the last stage is the push-pull amplifier. But there is ...
0
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1answer
47 views

How to increase the output power for this audio amplifier?

I have created this simple single stage, transistor audio amplifier using voltage divider bias. For testing, the source of input signal was audio from laptop and the output was from a 4 ohm, 0.25 ...
3
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1answer
35 views

how does this differential ddr receiver work?

I'm looking at this simple schematic trying to understand how a DDR SSTL receiver works (the one on the left). I get that the input voltage will be compared to Vref and the output will be a ...