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Questions tagged [transistors]

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

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How to set fixed bias on transistor 2N2222 for certain specifications?

I'd like to ask how to set fixed bias for this transistor.. It doesn't seem to be working. If anyone know how to calculate it, please tell me. I wanna adjust two resistor values so that Uce = 5,44V, ...
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39 views

NPN Transistor 2N2222 fixed bias MULTISIM

I have been working on my school projects and I wanted to ask you if there is any way of editing BETA for transistor. When I click on transistor, Edit Model is not working. Anyone help me, please.. I ...
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48 views

Motronic 1.0 component identification

Trying to identify a transistor, ON698 6N608 ? GR608 ? part of ignition coil driver circuit on Motronic 1.0 dme on 80's BMW or Porche Hard to read ??
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32 views

R_on for inverter gate

What \$R_{on}\$ do I use to calculate the delay for an inverter gate? In my class we came up with two definitions of \$R_{on}\$, one for saturation and one for triode. Is there a certain mode I ...
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104 views

Selecting a transistor, is there a go to transistor for typical projects?

I'm a HVAC tech who is interested in electronics. I have 3 kids and not a ton of time to really get involved with the data sheets or a real understanding of electronics. I just want to make some ...
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43 views

How is a transistor power calculated

I refer to a 2N3055 power transistor, the spec. sheet gives the following: Max. current 15A, Max. Voltage 50V, Power rating is 115 Watts. What is the power rating calculated on? If it is E*I ...
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68 views

What can be alternatives to BF494 transistor?

I am currently working on a project which involves a RF Amplifier. I found BC494 to be quite suitable for the same. Though, I am looking for its alternatives since I couldn't get one of these.
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55 views

Power consumption open collector/drain

https://www.allaboutcircuits.com/technical-articles/the-i2c-bus-hardware-implementation-details/ I read from this article that for the open drain there's nontrivial power consumption when the input ...
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91 views

555 timer circuit switching automotive solenoid with PNP & NPN switching transistors

I am trying to design a 30 second timer circuit to switch an automotive solenoid that draws about 0.8 amps, and need some help please. StackExchange posts have been very very helpful so far, and by ...
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64 views

Asymmetrical Schmitt trigger circuit

I'm designing a circuit to switch a solenoid with hysteresis. I'd like to switch the solenoid off, shown by R12, when the signal is above 0.8V and switch it back when it's below 0.7V. With the ...
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73 views

Can I apply Kirchoff's law in the open contour in the picture

So is it right if I apply Kirchoff's law : Vcc=I1R1+I2R2+I3Re if I1 is the current that flows in R1 resistor, I2 in R2 and I3 in Re
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How does the biasing work in a JFET based triangle to sinewave converter?

To those who haven't see this cool little circuit it employs the non-linearity and symmetry of the JEFET to clip a triangular signal to make it more sinusoidal Can someone please explain to me how ...
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36 views

Finding the voltage of base Vb

I wanted to know if Vb in the trasistor in the photo is equal to the formula in red circle: Vb=R2*Vcc/(R1+R2)
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73 views

Find output impedance of BJT amplifier

I need to find the output impedance of the BJT amplifier as shown below: The equivalent small-signal circuit looks like the following: I know that the output impedance is $$Z_o=R_{E1}\ ||\ (R_{E2}+...
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80 views

total newbee question : use transistor as a switch

Ok, I don't know anything about transistors, and my knowledge about electronics is basically limited to U = R . I and ...
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3answers
82 views

Multiple Vibration sensors via single optocoupler

I am designing simple security system to protect 20-30 windows (total length about 50m) with vibration sensors (based on SW-420 modules). Window are on the roof and due to environment i use ...
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125 views

Do I need a resistor on the base of a transistor?

When I am connecting an IO pin of a microcontroller to the base of a transistor, do I need a current-limiting resistor between the IO pin and the base? Or can I just directly connect the pin? My ...
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76 views

BJT common collector amplifier with a voltage gain sligthly higher than one

How could I explain why a common collector amplifier has a voltage gain higher than one ? In a lab session, I built this circuit : With Vg=30 mVpp and Vcc=15V, students were asked to give the voltage ...
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52 views

Amplification equation for AC coupled Common Emitter stages

Do anyone can tell me how to get amplification equation for this circuit of coupled common emitter amplifier? simulate this circuit – Schematic created using CircuitLab Edit 1 Equation for ...
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53 views

Transistor Inverter - when does excessive small wattage become a problem?

I'm trying to choose the best values of resistors given the stock I have so that I can deliver sufficient power and current to an HM-TRP radio module. In this circuit, I used the 100K resistor ...
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3answers
84 views

How to configure NPN transistor as switch and adjust current flow?

Consider the following circuit: As signal a 100 kHz square wave (between 0 and 5 volts) generated by an Arduino. I want to control the transistor so it will let the current from the supply pass ...
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116 views

Transistor weak current when switched from microcontroller

I have ATMEGA328 (running on 5V) connected to a C4793 NPN transistor which controls the TEC1-12706 thermal component. I'm using the code below to turn the transistor on and off: ...
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143 views

What does a transistor look like in the Intel 4004 microchip?

Could anyone show a picture of what the transistor looks like in the Intel 4004 microchip? There are 2300 transistors in that microchip.
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58 views

Do BJT (Darlington) transistors have a minimum collector current?

I am using a TIP122 Darlington transistor. From the graph provided in the datasheet, I can see that the saturation voltage decreases as the collector current decreases. Since the load I am driving ...
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44 views

What to do when you don't find an electric component in Proteus?

I am looking for this component: KSC1815. It is a NPN Epitaxial Silicon Transistor The datasheet is here: http://www.futurlec.com/Transistors/C1815.shtml But when I try to pick that component in ...
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51 views

Using 2N2222A transistor to switch on/off NodeMCU board

I was trying to make a battery powered project by using a NodeMCU board. To avoid desoldering some parts to achieve low consumption (Like the regulator or the UART chip) I intended to use a small ...
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2answers
68 views

Siren sounds weird when driven through NPN transistor

I'm trying to drive a 6-28VDC siren from an Arduino Nano output pin. The latter provides 5V (max 50mA). I've connected Arduino output to base of NPN through a 100k resistor, with emitter to ground ...
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13 views

Effect of base doping on early voltage,base transport factor and emitter injection efficiency?

According to me as base doping increases recombination will be less at base region so base transport factor and emitter injection efficiency will increase and as effective base width will decrease due ...
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55 views

Design a DC motor with a transistor

I am trying to design a DC motor with transistor. Following image shows the exact way I am trying to do so. How would I go about doing so, I am not so familiar with transistors, but something that ...
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44 views

Base of transistor HIGH without input [duplicate]

I'm having trouble with a simple AND gate, using two 2N2222 NPN transistors: For some reason, the base of the second transistor is high at 2.9V and I don't know what's causing this. I have verified ...
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43 views

Transistor count of a shift register

Static RAM requires, as I understand it, six transistors per bit. How many transistors per bit are required for a shift register, of the simple serial in serial out variety? Is it likewise six ...
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34 views

DC and AC analysis of a Common Emitter Amplifier Circuit

What we know about the circuit is that in DC-analysis (when \$V_{in}=0\$), \$V_{out}=10V\$. We also know that the circuit (even outside of DC analysis) will have \$I_{C}=2mA\$ and \$V_{CE}=5V\$. \$R_{...
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138 views

How to switch a 12V DC (3A) Motor with a 3.3V signal? [closed]

I was previously using a 2N2222A transistor with a small dc motor and it worked fine. As soon as I used it to control the 3A motor, The circuit stopped working. Is there any way I could control the ...
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60 views

BJT Astable Multivibrator - What is the max. oscillation frequency?

What is the max. oscillation frequency of this Astable Multivibrator circuit? Is it directly related to transition frequency of the transistor? I plan on using it with BC547B transistor. The hardwired ...
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MOSFET construction

I've just read an application note and I was confused about this sentence: "Engineers often think of a MOSFET as a single power transistor, but it is a collection of thousands of tiny power FET cells ...
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74 views

Replacing NPN Transistors that failed with similar/better?

I have done some research about this before hand(https://www.electronics-notes.com/articles/electronic_components/transistor/choosing-replacements-transistors.php). I have a switching 12v dc power ...
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53 views

The collector current of BJT

On what parameters does the Ic collector current of a transistor depend upon, base emitter voltage or base current? I know that BJT is a current controlled device. But still we have graphs that show ...
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59 views

Replace mechanical switch with electrical switch or relay

I have a remote controller for a portable heater, and I am working on a small project to be able to control the fan on/off from an arduino with Bluetooh HM-10 module. I thought a solenoid might work ...
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94 views

AND gate made out of transistors letting current pass despite only one input high

I recently built a gate with transistors, however my meter reads 1.6 volts when only input B is high, and 2.3 while both are high. How can I fix this? (I used 3 volts instead of 6 and 2k instead of ...
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795 views

Understanding class A amplifier waveforms

I am working on an audio amplifier but got stuck on to a basic of npn transistor circuit. Attaching a class-A amplifier circuit. Take a look here or here. I tried to simulate the circuit but as ...
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50 views

Using an arduino to control whether or not a phone is charging or not

I am working on building a circuit that is controlled with an Arduino Pro Micro. It is being fed by a 3.7V 5000mAh battery which is also going to be used to charge the phone, but only when the Arduino ...
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58 views

Why is this transistor failing?

I have a Sharp LC-19SB24U Monitor that tends to blow a fuse on the power supply. Every time it does, the FET (FQP8N60C) has also gone bad. So I replace the FET (with thermal paste) and the blown ...
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83 views

MOSFET Power Supply Explained

I am struggling to understand how the jumpers at the bottom of this diagram change the voltage of the circuit in this diagram. The input J1 is a 9V wall wart. By my understating the MOSFET only ...
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39 views

Upgraded flipflop square wave generator - did I do good?

I've drawn up a simple multi-frequency square wave generator, based on a astable multivibrator circut, with frequency trimmed by the two ganged pots (both 100k) and the range set by a DPDT switch, ...
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1answer
38 views

How does current sink help in biasing the differential amplifier?

Here M1 and M2 are differential pairs with analog input. When source resistor is used Rs M1 and M2 when Vgs is less than 0.7 Vt threshold M1 and M2 will be in cut off region and Vo1 and Vo2 will be in ...
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70 views

BJT: Finding Ie and Ib [duplicate]

I am struggling to find out the Value of Ie and Ib here. Ic I have taken to be Vcc/10k. If this is correct I could use Ic/alpha = Ie . I would like to know if this is the case but seems to easy to be ...
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47 views

Relay switch not switching

So I purchased a min 3V relay switch (https://www.digikey.com/products/en?keywords=ADW1103HLW) and am trying to turn it on with a simple transistor setup. The data sheet says I only need about 66.7mA (...
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2answers
78 views

Transistors: Quiescent voltage and Active mode

I am struggling to understand two things about this circuit. 1) when input and output terminals are open circuit, why is this assumed to be in active mode? 2)What range can the quiescent output ...
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4answers
127 views

Controlling 12V Magnetic Latch Solenoid with RaspberryPi 3b

As the title says I am trying to control a solenoid with a raspberry pi. I am currently using an npn transistor (will post link with parts at the bottom) however I am having a hard time getting it to ...
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70 views

Is this mosfet stable? Trouble with capacitances

I have the following circuit and I'd like to know about its stability : From what I've learned from basic electronics courses, the first step is to add the parasitic capacitances. I know there is ...