Questions tagged [npn]
A type of bipolar transistor comprised of n-type semiconductor in contact with p-type semiconductor which in turn is in contact with a n-type semiconductor -> thus NPN. The transistor has three terminals, the Emitter, Base and the Collector. Current injected into the base controls the flow of current from Emitter to Collector enabling amplification and switching.
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How to derive voltage gain in Common Emitter (CE) NPN BJT configuration?
Looking at Microelectronic Circuits - Sedra & Smith,
I understand how to determine eq (7.9), and I know eq(7.12),
can someone share a step by step derivation to determine eq(7.20)? Thanks!
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What have I built exactly?
I was fooling around with cmos inverters and then I saw what was happening when I tried to increase the gate voltage past Vdd/2 so I tried to take advantage of it and connected it upto a darlington ...
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Does Vceo works when 2 npn transistors are connected in series with one of its base open?
We know that in npn transistor BC547, when its base is kept opened/disconnected, there is a reverse breakdown voltage from collector to emitter when the supply voltage say 52V DC is greater than the ...
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Common Collector, Load Resistor Voltage Confusion
Using this link as reference: https://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/common-collector-amplifier/
In this section of the book, the author was describing that the voltage of ...
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NPN transistor base doesn't drain as much current as I calculated
I am very new to transistors unfortunately, so sorry if I don't know every formula already.
The thing is, I would like to use a bipolar NPN transistor as an amplifier. It has a current gain of 200.
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Cut Off mode of an NPN transistor with PSPICE
]2
I am trying to model the cutoff mode of an NPN transistor with a switch that is connected to the base. Unfortunately, it shows current going through. I am using ORCAD Capture.
Does anyone know ...
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How to turn an LED on in an inverter circuit
I am currently trying to build an inverter circuit which turns on an LED (on a simulation before building it physically). I am using an 2N3904 NPN transistor, 5V voltage sources, a 220k and a 47k ...
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How can I increase the base-emitter voltage of an NPN transistor in forward active region?
For a project which involves amplification, I think I have to increase the base voltage, keeping the emitter voltage the same so that my circuit will not go out of forward active region as the ...
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What would be the values of R1 and R2 to activate the 12V (SRD-12VDC-SL-C) relay?
Hello, I have a circuit which will act as AND gate consisting of 2 npn BC547 transistor to activate a 12V DC relay.
Relay is SRD-12VDC-SL-C whose datasheet is at https://www.alldatasheet.com/datasheet-...
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Where does the 1 V voltage come from?
I have a PLC with many digital open collector outputs connected similarly to the schematic below.
If I use a multimeter and measure the voltage between the two points in the schematic, it is showing 1 ...
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Drive BJT via Esp32 DAC
I've an ESP32 with a DAC pin that outputs a variable voltage between 0 and 3.3 V.
I need to drive a 12v motor using only a NPN power BJT like mj802g (or BUTW92, mj1403, NTE29, BUV21G, ...) powered ...
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BJT amplifier design
I am trying to design a BJT amplifier with the given parameters and limitations. The circuit is shown below.
Parameters:
Vcc = 15 V
RL = 20 kΩ
beta = 180
Vbe(on)= 0.6 V
Cµ = Cπ = 0
Limitations are:
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Low current continuity checker
Let me preface this by saying I have minimal electronics experience and reading data sheets is slightly confusing, but I get a gist of how most components work.
I am making a lower current continuity ...
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Time delay of LED dimmer circuit problem
I made a LED flip flop circuit using NPN transistor, it works pretty fine.
But my problem now is I don't know how to control the on and off time delay for the LEDs using potentiometer.
I tried putting ...
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Reduce active region of NPN transistor
I've got a small LED garden lamp, battery operated, that turns on with a switch.
I am currently trying to use a photoresistor that I have to make it turn on when it gets dark (so I don't have to ...
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NPN Relay Driver Problem
I've designed what I thought would be a simple relay driver circuit to drive a relay with a raspberry pi GPIO pin (which is pulled down with a 50K resistor internally). In the circuit diagram, pin 6 ...
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How do RF broadcast towers switch so much power so quickly?
Edit: I modified numbers below for a "licensed 1000 kW ERP channel", for which total true radiated power (being in a pancake shape since there is no need to radiate up into space) is ...
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NPN transistor won't switch off in boost circuit
I'm designing a boost circuit to generate ~150V from a 1-4 cell lithium battery. It doesn't need to supply a lot of current; I just need high voltage. Using a 4 cell battery with full charge (16.8V), ...
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I designed an opamp, any additions on how to make it better? (Closer to ideal opamp)
I'm not very good at electronics, but after learning for a bit, I designed a bare minimum opamp which has a differential amplifier and a Darlington NPN amplifier. Here is a picture:
I thought about ...
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How to activate a solenoid using TSOP4838 IR receiver
I have a TSOP4838 whose output is 5v normally and 2.5v when I press a button on my DVD remote. I wish to activate a solenoid when the DVD remote button is pressed. The circuit is is powered by a 9v ...
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Ebers Moll parameters for MPSA18 and AC128 BJT transistors
First of all, I should mention electronics is not my field so my problem might be trivial for you.
I'm currently working on my thesis and I need to model two BJT transistors: NPN MPSA18 and PNP AC128. ...
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NPN and PNP transistors for push pull amplifier
I always see that the NPN transistor is used in handling the positive signal while PNP transistor handling the negative signal in a push pull amplifier. What is the theory behind it? Can we swap the ...
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Arduino can not drive a BJT connected to a relay
I'm trying to make a simple 24V relay driven by an Arduino Leonardo as per the following picture:
The Arduino code simply toggles the output every 2 seconds. When I measured the pin voltage alone, ...
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Using the PLC output to mimic a NPN sensor as the input to a device
I got a device which has a connection to a NPN proximity sensor, it'll do something when the sensor is being trigged.
Now I remove the sensor, using a PLC(24vdc) to do the job of sending the signal to ...
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Why does the LED turn on in the following circuit?
I have connected a transistor as shown below, where
the base of the transistor is connected to the negative of the power source
the emitter is connected to the negative side of an LED
the collector ...
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NPN transistor small output voltage
I just learned about measuring the base resistor of a transistor but I think I did something wrong.
I wired everything up like this, but when I measure it I only get around 2.7V out of my device. Is ...
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BFU730F doesn't work on real experiment, what is wrong?
I have calculated BFU730F transistor on paper - all is ok.
I have created simulation for similar transistor (BFR740 because there is no BFR730) - all is ok.
I have maked shematics - it is not working. ...
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Designing circuit parameters with NPN-PNP transistors -LTspice simulation
Below is a part of the circuit I created to drive the MOSFET (it includes level shift, power stage etc.).
Datasheet of 2SC2411K: https://fscdn.rohm.com/en/products/databook/datasheet/discrete/...
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Typical output characteristics table of an NPN transistor
The Ic - Vce table for the 2SC2411K transistor is given below.
As it is known the right side of the table represent the breakdown region. That is, does the Vce > 5 V region enter the breakdown ...
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Correct use of a ULN2803A
Did I wire up correctly this ULN2803A?
I am trying to use it to power an RGB LED Common Anode strip ith a length between 50 cm and 1 meter, and a 24 relay with an Arduino Mega 2560
Thanks in advance
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LTspice simulation of Class B amplifier
In the 1'st picture below I provided the amplifier circuit diagram.
The 2'nd picture is showing the base signal of Q5 (green colour) and Vce signal of Q5 (blue colour). It is working as it is expected....
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Calculation of transistor values using hFE
I provided a very simple NPN transistor set up and hFE values as shown below.
2N2222 datasheet
I am trying to calculate parameters such as base current, collector current, Vce using hFE (beta).
The ...
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BJT NPN transistor
I am confused on a topic regarding NPN BJT transistors.
When there is a collector-emitter voltage (VCE) applied to the NPN transistor (as shown in the figure) without a emitter-base voltage (VBE), it ...
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Driving Mosfets using NPN - PNP transistors in Ltspice [duplicate]
I sent the SPWM I produced to the transistor as seen in the diagram below. pwm frequency 10 kHz.
As seen in the 2nd picture, PWM-A works fine.
As seen in the 3rd picture, I shared the unzoomed version ...
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Output of TIP122 drops when connecting a load
I have built this circuit:
(the components here are labeled wrong LM317LZ is LM317T and TIP122G is TIP122)
When there is no load the output of TIP122 is 10V-20V (when adjusting potentiometer) which ...
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Battery Charging Circuit - What is the operational analysis of device Q1?
simulate this circuit – Schematic created using CircuitLab
V1 is a 24 volt dc 210 milliamp power adapter. V2 is a 14.4 volt nominal nicad battery in a handheld vacuum. V1 is almost 30 volts open ...
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Used Transistor as Switch LED
I designed simple circuit using transistor as switch for my led. I used npn transistor. The input voltage is 46V. The current input is 15mA. My question is my circuit is correct or not?
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Why doesn't this NPN transistor AND gate work?
I am trying to form an AND gate using 2 NPN transistors, but the LED lights up when I turn on the right switch and the left switch doesn't make any change. Can someone please point out the problem?
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What is this NPN circuit doing?
I'm trying to make a mod to a board from a device I have, and I'm trying to decipher what a particular circuit on it is doing. I'm somewhat of a hobbyist in circuits, but I'm not 100% sure whats going ...
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What happens when the CB junction is in forward bias and the BE junction is in reverse bias in an NPN bipolar transistor?
What happens when the CB junction is in forward bias and theBE junction is in reverse bias in an NPN bipolar transistor?
I thought of two possibilities:
The NPN transistor acts as it is but in ...
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NPN transistor as a switch configuration
I have a npn transistor configured as a switch which is normally on and at times I have it switch off and on at 7Hz-8Hz, with R1 5.10k and R2 100k and 0 V to 5 V MCU pin and max \$I_C\$ current from ...
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ESP12 to switch computer power
Hi all!
I'am trying to use an ESP12S to turn a desktop computer on/off remotely, using a NPN 2N2222 transistor, while also trying to keep the physical power button working.
Much like this project:
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Eliminate effect of VBE in NPN transistor to maintain same gain ratio for a low dc input signal and at all operating voltages
Good day,
To monitor the current flowing through a varying resistor load across all supply voltages (8V to 20V DC), I am connecting in series, a small fixed sensing resistor and the drop across this ...
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How would the Collector Current be affected during Saturation mode in a NPN Transistor?
From my knowledge,
In active mode of operation of a NPN transistor, Base-Emitter Junction is in Forward Bias, and Collector-Base Junction is in Reverse Bias. Width of Base is very low.
During ...
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Does a negative base current in BJT npn mean that the operation mode is Reverse Active?
Given Vce = 2V, Ic = 1.7mA, and Ie = 1.6 mA, I used KCL to determine that Ib = -0.1 mA. Does this mean that the BJT npn is in reverse active mode?
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How can I calculate the base current required for my multistage connected PNP transistor to obtain an obtain an output collector current Ic = 1.5A?
I need to design a circuit that provides an output of 11.5V with a current of 1.5A. This output is drawn from a TIP42 PNP transistor. The transistor gets its base input from a NPN2222 transistor.
The ...
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"Normally closed" switch with NPN transistors
Is it possible to have "Normally closed" switch with NPN transistor when the voltage at the base is 0V? So far I only managed to achieve this result with NPN transistor when the base is HIGH. When the ...
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Pre-biased NPN BJT slow turn-off
In a PCB design I decided to replace a 2 kΩ resistor plus a MMBT3904 with a dual NPN transistor with built-in resistor in a SOT-363-6 package to save space and number of components. The part is ...
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Arduino - Using NPN transistor as a switch to pull-up/down analog pin
Let me start by saying that I am not an EE, and my knowledge in Electronics is basic, so please bear with me and be patient if, initially I am bending a few rules.
In Epee fencing, a touch is awarded ...
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Why would I use 2N3904 instead of 2N4401?
2N3904 and 2N4401 appear to be very comparable parts in all specs. 2N4401 has a higher current rating, but otherwise they look to be about the same in price and everything else. Obviously it's ...
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