transistor help

Started by Imran in sci.electronics.basics11 years ago 2 replies

Hello, I have a home irrigation controller hat has gone faulty on one of the zones, I have opened it up and have found one of the transistors...

Hello, I have a home irrigation controller hat has gone faulty on one of the zones, I have opened it up and have found one of the transistors to be faulty there is a number on the transistor but it looks like its a part number from the manufacturer of the irrigation unit rather then the actual part number of the transistor. The number written on it is 1401ES or 1401E5 cant make out i...


transistor.....

Started by chra...@gmail.com in sci.electronics.basics11 years ago 5 replies

why a DC-supply is given to a transistor?

why a DC-supply is given to a transistor?


What is the proper way to turn off a positive voltage supply with a NPN transistor?

Started by Mr. J D in sci.electronics.basics11 years ago 3 replies

I want to turn off a load that requires about 200mA. I am only familiar with the common emitter setup for a NPN transistor, which cant be...

I want to turn off a load that requires about 200mA. I am only familiar with the common emitter setup for a NPN transistor, which cant be used to turn off a positive voltage supply. I am unsure of the proper technique for the other setup that allows for the control of a positive voltage. Thanks.


PC component identification - major newbie...

Started by Vespa in sci.electronics.basics11 years ago 3 replies

Hey, So, I'm trying to ID the components on the board of my cars cruise control board (it's broken). Now some I know, like a component...

Hey, So, I'm trying to ID the components on the board of my cars cruise control board (it's broken). Now some I know, like a component with "R43" next to it is a resistor, or "C12" is a capacitor, "Q16" is a transistor, and "D1" is a diode. But here are a few I don't know and would like help IDing: "RA3" - "X1" - "IC7" - (integrated circuit?) - That's it. School me! Thanks, Paul ...


How Pixel works?

Started by Anonymous in sci.electronics.basics11 years ago 3 replies

I have done my homework (doing research). And I still like to understand how to activate a pixel with a different color. I know that within a...

I have done my homework (doing research). And I still like to understand how to activate a pixel with a different color. I know that within a pixel, there are three phosphor dots http://en.wikipedia.org/wiki/Pixel http://en.wikipedia.org/wiki/Pixel_geometry http://electronics.howstuffworks.com/lcd9.htm And millions of of Transistors are needed http://en.wikipedia.org/wiki/Transistor ...


basic transistor switch with input from parallell por( i know it's been discussed) but i need help

Started by aiwarrior in sci.electronics.basics11 years ago 7 replies

Hi im near the point of giving up of trying to learn electronics... My problem is that i cant switch a relay with my parallell port trough a...

Hi im near the point of giving up of trying to learn electronics... My problem is that i cant switch a relay with my parallell port trough a transistor. The design is basic and calculum too..and i wander whats wrong. Please tell me what am i doing wrong so i can get back on track :D Transistor 2N2222a : Vbe = 0.7V Vce sat = 0.3V hfe = 10 Icmax = 500mA Vcemax=100V Relay: Rr = 426o...


Another simple transistor question.

Started by AJ in sci.electronics.basics11 years ago 7 replies

Hi all I know that a PNP transistor will not work if the collector is higher than the emitter but will it be damaged? Regards, AJ

Hi all I know that a PNP transistor will not work if the collector is higher than the emitter but will it be damaged? Regards, AJ


Tri-state with transistor?

Started by FyberOptic in sci.electronics.basics11 years ago 9 replies

Hiya folks, I'm not up to speed as well as I probably ought to be on analog electronics, but I have a particular case where such a thing might...

Hiya folks, I'm not up to speed as well as I probably ought to be on analog electronics, but I have a particular case where such a thing might be simpler to implement than adding in a whole 'nother IC for one logic connection, so I thought I'd ask the smart folks to verify something for me. Basically, I want to be able to toggle between tri-state and ground for a single signal. Here's my ...


My first transistor circuit

Started by Marc Britten in sci.electronics.basics11 years ago 17 replies

I'm pretty new to electronics, I've pieced together a few circuits from schematics and I even made a simple LED light display by hand with a do...

I'm pretty new to electronics, I've pieced together a few circuits from schematics and I even made a simple LED light display by hand with a do it yourself pcb kit and a circuit of my own design (nothing terribly original). I'm currently trying to play with transistors and I came up with a project. I have a small heating element for coffee cups thats designed to run from the standard powe...


quick emitter follower question

Started by tempus fugit in sci.electronics.basics11 years ago 24 replies

Hi; I'm thinking about using a simple 1 transistor emitter follower in an audio design (the audio signal will pass thru it). Does the noise...

Hi; I'm thinking about using a simple 1 transistor emitter follower in an audio design (the audio signal will pass thru it). Does the noise figure of the transistor need to be taken into account, or will there be no noise added since there is no amplification happening (sort of like the signal just 'passes thru' the transistor untouched)? Thanks


Audio amplifier

Started by sahil in sci.electronics.basics11 years ago 8 replies

Hi , I am using an audio amplifier of transistor 2N3055 .It uses two transistors for one channel and 4 for two channel amp.I have two channel...

Hi , I am using an audio amplifier of transistor 2N3055 .It uses two transistors for one channel and 4 for two channel amp.I have two channel amp with 4 transistors and using it with computer.The woffers used are one is 10 inches and other is 12 inches .I want to increase the power of amp.What i shoud do ? i am using 12-0-12 ,1A transformer.Help me to inprove its performance.........


SMPS Inductor saturates?

Started by Bill Bowden in sci.electronics.basics11 years ago 14 replies

I'm building a small Boost regulator using an inductor, transistor switch, diode and filter cap, but I cannot get enough current into...

I'm building a small Boost regulator using an inductor, transistor switch, diode and filter cap, but I cannot get enough current into the inductor before the transistor starts dropping a large portion of the supply voltage. I don't think the problem is related to the transistor gain or base drive since the circuit will draw a couple amps with just a DC input on the transistor base resistor, ...


How start a transistor at 3V when signal is very high impedance?

Started by James Harris in sci.electronics.basics11 years ago 11 replies

I understand that an NPN base-emitter junction needs a voltage drop of c. 0.6V so won't start turning on until Vbe exceeds that. Can I get...

I understand that an NPN base-emitter junction needs a voltage drop of c. 0.6V so won't start turning on until Vbe exceeds that. Can I get the transistor to start conducting when the input voltage (i.e. between the circuit input and ground, common emitter connection) is around 3V. I don't think I can use something like a potential divider or apply a bias voltage because the source may be of...


Transistor

Started by Beenu in sci.electronics.basics11 years ago 6 replies

Hi, I have a doubt. Could anyone help me with this? Let us consider a properly biased transistor. Let us assume that I have connected a...

Hi, I have a doubt. Could anyone help me with this? Let us consider a properly biased transistor. Let us assume that I have connected a load between the collector and the ground. My question is how does the load effect the transistor ? Does it change the operating point at zero signal conditions? thanks, beenu


[newbie] leds and 7432

Started by zoidberg in sci.electronics.basics11 years ago 2 replies

I need to link two green leds to one of the outputs of a 7432, but the output current is insufficient. What can I do? I thought that a cmos...

I need to link two green leds to one of the outputs of a 7432, but the output current is insufficient. What can I do? I thought that a cmos buffer (4010) put between the 7432 output and the leds can be a good solution. Could it work? Otherwise would a 2n3904 npn bjt transistor work? http://snipurl.com/wwsv


Audio Amp

Started by sahil in sci.electronics.basics11 years ago 3 replies

Hello friends .Its sahil wants ur help. I am currently using an audio Amp of transistor 2N3055 .It uses two transistors for one...

Hello friends .Its sahil wants ur help. I am currently using an audio Amp of transistor 2N3055 .It uses two transistors for one channel .Transformer is of 12-0-12 , 5A .I am not satisfied with the amp performance.I want some what powerful amp schematic whose transistors are easily available .I want to drive 12" SUB WOOFER. Hey I hope U are the person Who can HELP me......Reply .........


Newbie : Microprocessor A/D question

Started by Tim Jenkins in sci.electronics.basics11 years ago

Hi, I'm looking at an existing circuit trying to understand how it is built to further my electronics knowledge. There is a part of the...

Hi, I'm looking at an existing circuit trying to understand how it is built to further my electronics knowledge. There is a part of the circuit thats puzzling me though. The circuit has a 6502 microprocessor on board. One of the standard I/O ports on the micro is connected to the Base of a BC212 transistor via a 10K resistor. The collector of the BC212 is connected to the supply rai...


How do i see the polaity on a npn transistor

Started by ragnar_123 in sci.electronics.basics11 years ago 7 replies

How do i see the polaity on a npn transistor? i got a 2n2222 npn, and i am not sure how the polarity is. sry, but i am only 14 year old so...

How do i see the polaity on a npn transistor? i got a 2n2222 npn, and i am not sure how the polarity is. sry, but i am only 14 year old so please explain what you are saying - and my english isn't soo good either. btw i am building a relay circuit, which is controlled by the computer's parallel port. thanks


choosing a suitable transistor

Started by randomname in sci.electronics.basics11 years ago 8 replies

I need a transistor (used for switching, from 6v supply) that will power a maximum of 400mA. For now I'm using a TIP31 but this is blatant...

I need a transistor (used for switching, from 6v supply) that will power a maximum of 400mA. For now I'm using a TIP31 but this is blatant overkill. Will this transistor work instead: MPS3704 Also, which resister do I need to use? So I don't ever have to ask again, what's an easy way to compute transistor specs, and resistor values? Thanks, -sam


Q: feedback and input impedance in a emitter follower

Started by Peter Andersen in sci.electronics.basics11 years ago 46 replies

Hi there I have a problem with some calculations regarding feedback and input impedance on a simple one stage transistor circuit here:...

Hi there I have a problem with some calculations regarding feedback and input impedance on a simple one stage transistor circuit here: http://www.mespilus.dk/Feedback_1.pdf With the feedback circuit (R5 + C6) connected I can measure a gain of 8.85. The input impedance is 1,08Kohm. With the feedback circuit disconnected I get a gain of 105 and a input impedance of 4,11Kohm. The ...