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)

learn more… | top users | synonyms (1)

0
votes
1answer
26 views

Ardunio Curve Tracer Question

I am trying to follow this guide to make a curve tracer with an ardunio: http://www.instructables.com/id/Arduino-BiCMOS-Curve-Tracer/ If I use this these op amps: ...
1
vote
2answers
54 views

Transistor Logic Gates in One Breadboard

How can I make a combination of the 7 Transistor Logic Gate and putting those gate in only one breadboard.? I've seen the combination on this Topic: How to combine multiple transistor logic gates ...
0
votes
1answer
39 views

Error Logic Gates [duplicate]

I connect this 5 transistor and,or,nor,nand,inverter respectively into to switches to operate.. I also add Exor and Exnor.. the Exor I made consists of 4 Nand gates based on the nand diagram stated ...
0
votes
2answers
56 views

DPDT switch using only transistors

I have seen a number of similar questions but no one ever seems to actually answer this question, so let me pose it a different way. Let's suppose I am stuck on a space ship (so I can't go buy some ...
0
votes
1answer
36 views

set one output high at a time when multiple inputs are high

I'm making a small circuit for detect water level of our home water tank .here is the diagram. when water level is low i want to turn red led when water level is max i want to turn green one on and ...
0
votes
2answers
66 views

Uninterrupted current triggering transistor base

I'm still pretty much a electronics-beginner, I'm currently working on modifying a USB game-pad to use switches instead of buttons and I want LEDs to accompany the switches. The basic solution I was ...
-1
votes
0answers
46 views

Transistor Logic Gates Connection Error [on hold]

Can anybody explain to me what am I gonna do with the combination of this 7 logic gates? the AND, OR, NOR, NAND, INVERTER, EXOR, EXNOR. I am having trouble connecting them into 2 switches to operate ...
2
votes
2answers
42 views

Adjustable power supply simulator/reality

Hi im a student of computer engineering and im currently doing a project of a adjustable power supply it should be doing 0-30V but im getting some problems with the word adjustable haha,i got this ...
0
votes
1answer
31 views

Single transistor Amplifier analysis (Q point values)

Could somebody please check to see if what I have done is right? I posted a similar question a few days ago and someone said V(CE) is equal to V(CC)/2. Is it ok to do this? So I got V(CEQ) = 6V and ...
0
votes
1answer
34 views

How does this logic level converter on the Adafruit HUZZAH work

I am busy with a project where I am connecting a 5V(Amtel ATMega328) MCU to an 3V(ESP8266) via the serial port. Obviously I need some logic levels converted. I looked at the schematics of several ...
0
votes
2answers
41 views

Feedback op-amp voltage regulator help

I have made a voltage regulator: simulate this circuit – Schematic created using CircuitLab And here is the zener circuit: simulate this circuit I have already tried to charge ...
0
votes
0answers
15 views

BJT VEB ratings availability

All Silicone transistors appear to have a reverse base emitter breakdown voltage rating of no more than about 8 VDC .It would be extremely useful to have a much higher volt rating . Some OLD ...
0
votes
1answer
86 views

Can I connect a MOSFET to an Arduino directly?

I have the following electromagnet and plan on connecting it to the following MOSFET which will be controlled by an Arduino (I'm thinking analogue or PWM). Do I need any other parts (resistors etc.) ...
0
votes
3answers
76 views

Transistor feedback loop

In an attempt to create a single transistor flipflop I made this : The Idea : When the base is triggered by a pulse ,current starts flowing from collector to emitter . From the emitter it divides ...
0
votes
1answer
32 views

Generalized transistor equation for Collector Current including the reverse saturtion current?

44I am referring to Millman's Integrated electronics and there I came across and equation $$ \begin{equation} (I_c) = -\alpha(I_E)+I_{Co}(1-\exp^{V_C/V_T}) -->eqn(5.6) \end{equation} $$ where $$ ...
0
votes
4answers
102 views

Transistor capacitor circuit . need help

This isn't working as expected. It should work like this: the led should stay on after pressing push button for one second. Although when I press push button once then led stays on for 4-5 minutes and ...
0
votes
0answers
42 views

Are SWITCHING PARAMETERS of mosfet important?

I was looking out for he AO4409 Mosfet for my Lenovo laptop motherboard.As i could not find it I came up with a replacement IRF9321PBF Mosfet which has got similar characteristics but different ...
0
votes
0answers
47 views

Constant current circuit messing up

I am working in a startup and facing some major issue with a led driving circuitry in pulse oximeter. Circuit is working fine with non smd components, but heats up to very high levels with an smd ...
0
votes
3answers
58 views

Darlington with 3.3V

I've been using TIP120 darlington transistors to drive various motors, I apply a 5V Base-Emitter voltage, that I sometimes modulate with PWM and a resistor on the base, this works great, but is there ...
0
votes
2answers
39 views

Low voltage drop transistor for Arduino

I am using a MQ135 gas sensor in my project. It takes a max of 200ma and I have connected the Arduino to a battery so I can disable it when needed to save battery. I am using a transistor for that but ...
0
votes
1answer
65 views

Power Switching with Microcontroller

I am in the process of designing a device for a uni project. As a requirement, we are required to have a very low power consumption whilst in standby mode. Our plan for this, was to have our 2 x +-5V ...
2
votes
1answer
43 views

Is BJT amplifier a viable option if the design needs to be replicated without calibration?

||Sorry for messing this up the first time. This is my first post ever in a technical forum. Need to pick up the ways of the crowd. Thanks for all the feedback and help. Well appreciated|| I intend ...
3
votes
3answers
68 views

Switching transistor off when current is supplied to it's base

Is it possible to switch off a LED when current is applied to base of a transistor? I am using the circuit below but when current is applied to the base, the LED is ON. I need the LED to be off when ...
2
votes
2answers
189 views

First chip with 1000 or more transistors?

I am wondering what was the first chip ever with over 1000 transistors? I already am aware of the following: The Intel 4004 was the first commercially available single-chip microprocessor and it ...
0
votes
0answers
57 views

Discriminating the use of a BJT from that of a FET [duplicate]

I've already read sufficient introduction to both BJT's and FET's, so I can identify Important differences such as current amplification v. transconductance, input impedances, power consumption, the ...
0
votes
2answers
109 views

What is the simplest way to make an AND gate using PNP transistors

I only have 5 PNP transistors and I want to build two AND gates. (for a T Flip-Flop) What would be the simplest way to make an AND gate using PNP transistors? (It can't use more than 2 transistors) ...
0
votes
0answers
31 views

Locating parts by footprint (Transistors)

I apologize if this is not broad enough, delete if you must. Is there a good way to search by footprint with any of the common distributors or manufacturers? I need to replace an NPN transistor ...
1
vote
0answers
62 views

Why are relays used in circuits when we have transistors? [duplicate]

Why do I find relays being used right next to transistors? What is the benefit or use of using a relay over a transistor switch?
1
vote
2answers
93 views

Audio amplifier controlling volume with Arduino?

I'm building a project that outputs audio via an Arduino to a powered computer speaker. This audio signal comes from a sine-wave-table lookup that I step through at various frequencies, setting a PWM ...
0
votes
0answers
20 views

Two-tone alarm issues

I'm working on an inclass project, for a two-tone alarm circuit. The 3V source represents two AA batteries. We've implemented this successfully on a breadboard. The IC used for the Inverted Schmitt ...
1
vote
1answer
66 views

Reduce gain of emitter follower

I need to reduce the gain of an emitter follower circuit to 50%. Can I do this by splitting the emitter resistor into two sections and taking the output from the junction? I am concerned that I will ...
3
votes
2answers
336 views

What is the meaning (definition) of “current-starving”?

In several circuit descriptions we can find the term „current-starved“, „current-starving“ or „voltage-starved“. Example In chapter 4 (Current-starved voltage-controlled oscillator) we can read: ...
3
votes
2answers
133 views

What happens with transistor outside max temperature range?

Suppose I have an IGBT transistor rated for 60A, that has junction temperature range of -55 to 175C. What happens if I do not exceed max current, but I do exceed max temperature? The characteristics ...
0
votes
1answer
34 views

Signal Detector (Field Strength Meter)

Hello I have attached a circuit of a Field Strength Meter that I came up with, my target frequency is around 500Mhz. I was wondering if a design like this will even be able to tune to 500Mhz. I am ...
0
votes
2answers
60 views

lm324 if i feed it with Vcc but not grounded it,what the value isee on GND pin?

I have lm324 in my circuit and I connected Vcc pin To 5V, but GND pin is not connected (float), so What the value I see on GND pin ?
-1
votes
3answers
88 views

Voltage Regulators Transistors?

I am new to electronics and I was wondering, how can I distinguish a transistor from a voltage regulator and the opposite? For example here are 2 images, 1 of a transistor and 1 of a voltage ...
0
votes
2answers
71 views

Where to add a capacitor

So I have a small circuit that I made to flash some led's in sync with my music. It's just a signal from my speaker going into the base of my 2N3903 transistor and the ground of the led is being ...
0
votes
3answers
149 views

Understanding transistor circuits

I have been working my way through The Art of Electronics by Horowitz and Hill and I've just started the chapter on Transistors. I am having some difficulty in understanding this transistor circuit: ...
-3
votes
0answers
72 views

How Transistor works as an amplifier in this circuit?

I want to build a circuit to use transistor as an amplifier. I searched on google and found this circuit which uses transistor to amplify the audio. Is it only the transistor or any IC which is doing ...
0
votes
1answer
52 views

Designing transistor logic gates

How would one make use of transistor logic gates ? Take for example this transistor AND gate for example . In all logic circuits, the output of one gate becomes the input of another . Here the output ...
1
vote
1answer
40 views

Calculating resistor values for RPi circuit detecting AC current using H11AA1 and PNP transistor

I've got an electronic doorbell system (Aiphone IE-1AD) that sends a ~15Vac signal when the button is pushed. I used this blog post on detecting a signal on a similar door bell using a moteino ...
-4
votes
1answer
82 views

What are the resistances of the R1 and R2? How to compute? [closed]

This is transistor as a switch. I used KSP2222A transistor. How to compute the resistances! Thank you for any help.
1
vote
1answer
80 views

Using TTL logic, is it better to use a JFET or MOSFET switch for power?

Using a 3.3V (max. 8 mA) output pin off an Intel Galileo development board, I need to turn on and off a 18V DC motor. Is it better to use a JFET or MOSFET transistor?
0
votes
1answer
58 views

Why do we ignore parasitic capacitance in dc analysis of transistors?

Consider a transistor that has parasitic capacitance of the order of pico-Farads. Then at low frequencies, consider 10Hz $$X_C=1/(2\pi f C)$$ \$X_C\$ will be in the range of giga-ohms. ...
0
votes
1answer
65 views

How does a junction-less transistors work?

I have recently read in a book that in 2010,junction-less transistors were developed. I can't understand how a junction-less transistor can be used to amplify current or voltage with having any ...
0
votes
3answers
61 views

grounded emitter or common collector circuit or something else?

first of all, I'm sorry if I did not use the technical correct symbols for the circuit diagram, but I think it will do. I've multiple questions. Maybe someone can give me a hint. I'd like to control ...
1
vote
3answers
62 views

Voltage drop on motor controlled by arduino via transistor

I am using a transistor (TIP 122) to control a dc motor using arduino. Although the power source I use is measured at 6V, I only get 5V at DC motor(M1) when I use the transistor. Here is the ...
1
vote
1answer
79 views

Effect of negative voltage at NPN transistor base (interesting example)

I'm trying to understand the behaviour of an NPN transistor and two diodes connected to the output of an instrumentation amplifier [image below]. The transistor appears to switch on when there is a ...
1
vote
1answer
69 views

Transistors absolute maximum values

As you can see this a transitor AND gate and yet the LED glows when only one input is high, passing the current essentially through the base and emitter. I think I fried (I think) my transistor ...
0
votes
0answers
45 views

how to improve switching times of FinFET transistor?

simulate this circuit – Schematic created using CircuitLab I am currently working on my project and unfortunately I faced some problems which i cannot solve. My task is to create (i've ...