in my engineering club i was asked to build a driver circuit push-pull emitter follower.

I have no idea what this is. I have recently started an engineering club ( i am 14) and wanted some help with my homework. I am using my older brother account because he told me to found it out myself. i have until tomorrow to find the right circuit and then build it when i go to my club using a software called multisim. 

Asked by MohamedN3 3 years ago | last reply 3 years ago


what is this i found it at an yard sale and though it looked cool?

  i don't know what it is but if you can help me find out it will be greatly appreciated  got it from an old military guy selling stuff on the side of the rode and he said he made it but he did not remember what it was made form an old fishing box thanks agine

Asked by zgordon3 7 years ago | last reply 7 years ago


Radio Frequency Generator? Answered

Hi I am doing a project and it requires a radio (or anything longer than human eyesight) frequency generator. Is there any easy way i can do this, with parts from home or radioshack?

Asked by LiquidLightning 8 years ago | last reply 8 years ago


does anyone know of a good ultrasonic sound emitter i can make?

Working something that found in some old text to test a theory but need a nice small hand held design for a ultrasonic sound emitter where the frequencies can be altered by the turn of a knob can anyone help please direct me to a good link either here or to some other sight.

Asked by maskofdarkness22 5 years ago | last reply 5 years ago


I have a LED i cant light, no matter what. It has a little black dot in it. What kind of LED is that? Answered

Appearance: It is a common 5mm, transparent case, LED, being different from all others only by having this very tiny square dot over its anvil, kind of covering the reflexive cavity where the semiconductor (i don't know which) gets lit up. Other: I could not light this LED whit voltages from 1.5V to 3.5V. =O It came out of a photocopying machine, and was paired with an IR LED in some kind of emitter-receiver set. Other components of this set were a pair of smd resistors and a smd trim pot. Would it be and IR receiver or photodiode? UPDATE: I've took some photos of the mysterious LED. BUT, as no macro-enabled camera was available, i had to do the ghetto-way of photography. Soo: i have photos of it compared to the IR LED, and some photos of both anvils (IR, unknown), at 200x magnifying. Here they are. BTW, i hadn't tested the suggested circuits yet. =(

Asked by vinacarv 9 years ago | last reply 6 years ago


Mousey Junkbot light emitters

Hello there, When I check my IR light emitters, they are giving a different voltage, 3.5mV and 0.8mV. Do they need to be giving a similar value for the eyes to function properly? Also these values are much lower than the 0.6V quoted in the instructions. Any advive would be much appreciated.

Posted by LeonR 8 years ago


IR (infrared) "motion detector" of sorts, need help please

I am looking to build a sort if motion detector that works with 2 IR emitters, 2 IR receivers and a motor, the emitters and receivers would be  in 2 seperate circuits and lined up with eachother  (the emitters constantly on) and when the link to the receivers was severed (for example by someone standing between the emitter and receiver) the motor would rotate, if the left emitter-receiver combo was disrupted it would apply positive voltage to the motor and if the right emitter-receiver combo was dusrupted it would apply negative voltage, is this even remotely possible? Firezone

Posted by firezone 9 years ago | last reply 9 years ago



Transistor Swithching Voltage? Answered

Looking at this data sheet: http://www.datasheetcatalog.org/datasheet/stmicroelectronics/4136.pdf How much voltage has to be applied across the base and emitter to switch on a "TIP 3055" transistor? The V-be row is the only thing that looks like it is telling about that, but I don't think that's what I'm looking for (mabey it is?).

Asked by Jaycub 7 years ago | last reply 7 years ago


How do I connect the phototransistor and emitter in this tutorial?

Hi, I'm currently working through the above tutorial and am struggling with setting up the Phototransistor and Emitter. There is a circuit diagam on the third page of the tutorial but I cannot work out how to connect the Emitter and Phototransistor to the rest of the circuit. If anyone could advise me further I'd be very grateful. Kind regards, KugarWeb.

Asked by kugarweb 7 years ago | last reply 7 years ago



Need to connect LED driver/controller to LED emitter.

  I have a 8.4V SST-50 5-Mode Memory Circuit Board & a SST-50 LED emitter. From the lower board are 2 leads presumably from the power source. If so,  then where are the leads that connect the controller to the emitter attached?  Can anyone (knowledgeable) PLEASE tell me how to connect them. Be as specific & detailed as you can. reply to:gjax00n@gmail.com                                                                                Thanks big          cgc210

Asked by cgc210 7 years ago | last reply 6 years ago


IR Robot Control

The cheapest way of wirelessly controlling a robot is IR, right? I'm in need of help for a schematic for an emitter and a reciever (this will be my first IR project). Please don't tell me to google it because I've been looking around and all I've found were vague schematics. I'd probably want to use a 555 timer for the emitter, but the schematics were vague again. For the reciever would I have to use 4, along with 4 emitters to drive 2 motors independently? As in Motor1 front and back, Motor2 front and back?

Posted by guyfrom7up 10 years ago | last reply 10 years ago


Proximity Sensing with the Arduino? Answered

I am looking for a way to use the arduino, an IR emitter and an IR detector to use for proximity sensing. I have looked at a lot of tutorials but none of them seem to deal with detectors that only have two pins, most are for the sharp sensor. I am looking for a cheap alternative and would like to stay away from the Sharp sensor. I want to be able to pulse on and off the IR emitter and be able to read the reflective beam with the IR detector. I was able to do this with a reversed led connected to the IR detector, not sure why that worked but it did. I am trying to find the proper way to wire and read the IR level. When the IR emitter pulses, I want the detector to take a reading and then I am going to use that reading to determine how bright or dull a connected LED will be. Any help is greatly appreciated and I think with a little bit of guidance I will be able to do this =) ... wouldnt mind taking pictures and making an instructable out of this either ;)? Here are the emitters and detectors I am using: http://cgi.ebay.com/25x-5mm-Infra-Red-IR-LED-LAMP-940nm-Emitter-Receiver-/360316905034?pt=LH_DefaultDomain_0&hash;=item53e48fa64a#ht_1465wt_905

Asked by afreeland 8 years ago | last reply 8 years ago


What is the most basic IR Emitter/Receiver and/or PIR module Analog 10 led circuit?

What is the most basic PIR module basic 10 led circuit? I have tip31's, many different size resistors,iIR Emitters and IR Receivers also PIR module with white dome 2 adjustments, on 12v?

Asked by Sidener80 4 years ago


D.C input resistance of a BJT transistor in C.E configuration?

What will be resistance across base and emitter of BJT in C.E configuration

Asked by deepakmurali 6 years ago | last reply 6 years ago


sound emitter

i need to know how to make a circuit the will emit sound with levels as high pitched as a dog whistle i been looking around but i can't seem to find one which allows you to control the frequency along with the pitch and tone i'd appreciate any advice and or help on this along with any information leading to any good instructables on here that fit the discryption thank you to every who gives the feed

Posted by maskofdarkness22 7 years ago | last reply 7 years ago


BJT under saturation condition??

Under saturation condition base current is very large that voltage across Base-emitter junction of  silicon based BJT is more than 0.7 volt. In this condition the voltage at collector (Vc) is 0.2 volt. By kirchoff's voltage law Vc=Vce( imagine emitter is directly grounded) Vce =Vcb+Vbe. If Vbe>0.7volt how Vce=0.2volt? As Vce includes Vbe, it must also be more than 0.7 volt. But it is 0.2 volt wich is less that 0.7 volt. How?

Asked by deepakmurali 6 years ago | last reply 6 years ago


Translating a Schematic to a Circuit Board

I need help translating this schematic to a circuit board. As in which rows to place what due to emitters and bases. I'm new at this, please help.

Posted by dwatord26 8 years ago | last reply 8 years ago


How Can I Make A EMP Emitter? Answered

I would love to make an EMP, but i have no idea how to... I am sure i have the right tools and surely enough of the resourses to do so, i have a plethera of capacitors, some that are like 300,000 micro farads... My friend told me that those would come in handy... what else would i need and how powerful could i make it? Also, size does not really matter to me, as long as it works, I would be quite happy with it :)

Asked by Caboose98 7 years ago | last reply 5 years ago


Extremely basic laser tag setup?

I'm looking into building a cheap, easy to build, no frills (score, shot counter, reload, etc) laser tag setup. All I'm looking for are: - a modulated 40khz IR emitter, with a muzzle flash LED - shot sound (any easy way to do this with a piezo buzzer, or other really easy way?) - a receiver that sends the signal to a piezo buzzer connected to your ear I'm not gonna go for milestag, because it's too expensive to make my goal of 8 guns with, and I don't have the skills to make it (or time), but I will use its general emitter and receiver setup, just no fancy microcontroller. All I want is a "point and shoot you got me". I AM looking for a long range, though, equal to milestag guns, and for that I'm using its modulated emitter and receiver setup (to avoid sun interference... am I right?). So far I've seen this and this as for attempts at making something old school like this, but as electronic-circuitry inadept as I am, I can't put everything together easily without some help. I've included a photo of my schematic, created with the help of the above links and modified/simplified forms of the milestag sensor... please help with corrections. My primary questions are: - how do I add a sound output to the emitter? A beep is acceptable, but if there's an easy way to add a real shot sound, I'd go for that. - how do I limit the pulse to a short, like 0.25 second time period (I realize this was answered in one of the above links, but I need a circuit diagram or more noobproof explanation for it), then stop the beam? - how would I ground the LED (Vishay tsal 6100) and a non-ultrabright, red LED (the emitter output) in the emitter schematic (left)? Do I need resistors before the ground? - how would I add the piezo buzzer to the output in the receiver schematic? I'm using a Mouser part #  539-PT2130FPQ, in case there are resistors i should know to add. - do I ground the #1 terminals on the 3 terminal 40 khz receiver/demodulator? Originally, they would have been linked to the "data" wire on the milestag module. Please help a budding DIY electronics enthusiast out?

Asked by MadBricoleur 7 years ago


2x bipolar transistor? Answered

If I took 2 similar NPN transistors and connected both the bases together, both the collecters, and both the emitters, then put it into a circuit, what would the 2 transistors do? Would the maximum power dissipation be increased or something? 

Asked by .Unknown. 8 years ago | last reply 8 years ago


Would this schematic work?

Will this work? it's based on https://www.instructables.com/id/SCYCBXQFD80BUXI/Basically, what it should do, is when I aim the IR emitter (TV remote) at it, it'll go off for a few seconds. The goal is to hide it and piss off whoever is watching TV, and changing channels.

Posted by cvxdes 10 years ago | last reply 10 years ago


Nightvision glasses?

Im no pro but ive read that a digital camera can veiw infrared. Well is there a way to use a pair of sunglasses and rig up an old digital camera to them with the screen on the inside of the glasses and then attach ir emitters to the glasses so that i can veiw about 100 ft?

Asked by trf 9 years ago | last reply 6 years ago


What practical applications do PNP and NPN transistors have? Answered

I read about NPN and PNP transistors and I was wondering what type of applications are right for each type of transistors. I understand that depending on the type of transistor the emitter should be connected to either an anode or cathode.

Asked by blkhawk 8 years ago | last reply 3 years ago


What to do with old robot? / Cybot

I found an old robot that was part of one of those 'build it yourself' magazine series. I was gonna eBay it but found there was actually quite alot of cool stuff in there so I've compiled a list and I'm gonna make an instructable using some of the parts, But I need ideas / help.Here are (the best) parts.2x sets of ultrasonic emitters / receivers2x LDRs large2x smaller photoresistors (used for line following)2x set of inrfa red emitter& reciever leds2x bright white leds + various others2x 9v motors & gear housingsLCD display 5cm squreeepromspeed controllers selector switches etcand a load of pre programmed processors that can't be reused.some more technical details here

Posted by madmanmoe64 10 years ago | last reply 6 years ago


InfaRed (IR) Motion Sensor

So...If I buy an IR Emitter LED and an IR Receiver LED ...and put them face to face...and get power to each of them....Can I somehow create a motion sensor out of that? For example, if someone walked between the 2 LEDs, it would trigger lights to go on. Is that possible?

Posted by Joe426 11 years ago | last reply 7 years ago


Phase shifting?

I've been considering building my own ground penetrating radar unit rather than pay outrageous rental fees and mind boggling full prices and I keep coming back to the same problem: time of flight is haaaard. My most recent thoughts on how to go about collecting that data would be to use 2 clocks/crystals that are offset from each other by fractions of a percent(one would be straight from a rubidium standard, and the other from a frequency multiplier). One would be in charge of timing the emitter and the other for timing the receiver. This is the part where I make tons of assumptions about things I know nothing about, so correct me if I'm wrong.      The emitter is running at f1 and it emits a short pulse.      The receiver is running at f2 and collects data as fast as it can until the reflections dissipate.      The emitter pulses again      The receiver, due to the f1:f2 phase shift, is offset by a tiny amount and again collects data as fast as it can. This cycle repeats until the collective phase offsets brings it back around, building the image . My thinking is that this shift, given the time to cycle around, could provide data that is functionally in the range hundreds of GHz, provided the target doesn't move(which at milliseconds per dataset, is functionally true). Could this work?

Asked by The Ideanator 5 years ago | last reply 5 years ago


What are the specs for 'standard' 3.5mm mono pluged infrared (IR) emitters?

An example of what I'm talking about can be found on Amazon.  I am looking for which conductor is anode and which cathode as well as the forward voltage and current requirements.  My inability to see IR is really hurting my normal LED testing techniques.

Asked by EmperorMing 8 years ago | last reply 8 years ago


3D Glasses setup? Crystal Eyes?

 I recently found a old pair of Crystal Eyes, and i recognized them as 3d stereo glasses, i found alot of wires, a manual, and an emitter box. I was wondering if their is an easy way to connect them to my computer I have a 8800GT and a Gateway 24inch monitor

Asked by snowluck2345 8 years ago | last reply 8 years ago


what makes collector current to be beeta(current amplification factor) times base current?

What makes collector current to be beeta(current amplification factor) times base current? Is it because of shape of the transistor or doping? or Why it is acting as constant current source? or Why the collector current is independent on collector resistor and Vcc(voltage across collector and emitter)?

Asked by deepakmurali 6 years ago | last reply 6 years ago


High Power LEDs

I have 3 10 watt LED emitters to sell (2.9 cm x 2.0 cm x 0.3 cm) Colour temperature is about 6000K I'll ship anywhere in Australia I don't have a good quality camera right now Send me a private message and I'll see what I can do

Posted by .Unknown. 6 years ago


How a Transistor connected to 12v and out 4.7v !!!!!!? Answered

Hello All, I have a problem with a circuit i am building, I use a 2N2222 transistor to drive a Common Cathode big 7 Segment  with a 595 shift register.. I connected a 12v to Emitter, the collector out a 4.7 volts !! How is this possible ? could some one explain please ? Thanks all

Asked by EZELab 6 years ago | last reply 6 years ago


Some advice on an RFID idea i have?

Realistically, how difficult would it be to DIY a passive RFID system where the tag simply reacts by lighting a low power LED. Catch is, i would want it to have an effective range of at least 1m. Could i build the EM emitter myself, or would i have to buy a high power reader?

Asked by R3born 6 years ago | last reply 6 years ago


Calculator IM

At my school we are required to have these TI-83 plus calculators for math. Of course we have classic games and stuff that we put on there, but we want to try to put an infrared emitter and detector on it so we could send IM's within the room to each other. Kinda like texting. Could anyone help us by suggesting ways to do this?

Posted by Jordo 10 years ago | last reply 8 years ago


Triggering a flash circuit with a voltage pulse across a transistor

Hi All,        question from a newbie. I'm working on a project for my (steampunk) daughter. For part of it I've taken the flash circuit from a disposable camera (PDF 1:Flash+MechanicalTrigger). This works just fine when I close the trigger mechanically. What I want to do is trigger it with the same pulse (from a 555 timer) that I'll be using to do other things at the same time. To this end I added a transistor as shown in PDF 2:Flash with transistorTrigger. My intention is to feed the 555 pulse to base, saturating it and triggering the flash. Result, abject failure. Help! The proposed triggering transistor is an MJE340(NPN). When set up as shown the indicator LED glows but voltage across Emitter-Base produces no result. When testing I noticed that if I mechanically make the collector-transformer connection it triggers a flash, even with no voltage across emitter-base. I'm stumped. Any ideas very gratefully accepted. Thanks, Fred.

Posted by fredstein 7 years ago | last reply 7 years ago


pinout help for my salvaged ir sensor/photo diode from mouse.?

I have salvaged ir emitter sensor pair from an old optical mouse. ir led glows fine on testing with mutimeter but the sensor part has 3 legs and i have always worked with 2 leged photodiodes . what is this specifically called? how can i know its pinout by testing with multimeter?

Asked by Atul009 4 years ago | last reply 1 year ago


How to make a DIY relatively long distance radio signal emitter/tracker? Answered

Hi, This is a bit of a two-parter. The first part is that I would like to make a DIY radio emitter that could transmit to a distance of 1km. I'm not sure about the laws in South Africa, but it should be legal if within the ranges prescribed by the law. The second part is that I would like to create several devices that could track the nearest radio signal on a specific band or band range (as I would expect that I would have to use a filter for both the transmission and receiving). I think that direction of the source of the signal would be sufficient.  The reason for this is that I have had a few instances over the years where people got lost while camping and had to sleep in the wilds because it was too dark to find their way back to camp. Any advice, thoughts, links would be much appreciated. Also, if you have any other ideas that will cost about the same or less, that would be awesome to try out, too :) Best regards, Vuur

Asked by Vuur 2 years ago | last reply 2 years ago


Wanting to make a switchable IR night light

Every night I come home, I have to open my garage door manually and park my motorcycle. When the garage closes, its dark and I tend to bump into my cycles exhaust burning myself. Yeah pretty funny. Anyways I had an idea, since I already had an arduino uno board and an IR Sensor and emitter, I wanted to make a trigger-able light switch. But I wanted my IR reader to run on AC, like a night light. At the press of a button from my emitter, the IR would pick up the codes and my light would turn on. Is this possible? Some people say, just buy a motion sensor and plug it in, I say i'll just salvage it for parts and try to make my own. Whats the fun in buying it, when I could build it with parts I already have. I mean, I know AC is dangerous, if not viable, then I could resort to a 9v with a power capacitor so long as it doesn't drain my 9v instantly.

Posted by bprins 3 years ago | last reply 3 years ago


High Voltage Amplifier

I am trying to build a high voltage amplifier that will amplify an AC signal of approx. +-5V to a signal of approx +-100V.  I was looking into building a common-source amp using JFETs or a common-emitter amp using BJTs, but both seem to have an output waveform of 0V to +100V.  Is there a way to modify these amps to have an output waveform of -100V to +100V?   Also, if anyone has any better Ideas, please let me know. Mark

Posted by questionmark05 8 years ago


Help

I need some help translating this diagram to a small printed ciruit board I bought from radioshack. I've never done this before and wish to learn. I decided to build this lie detector for my science class science fair project and have all the necessary equipment, I just dont know like what row to put what and emitters, base, and all that good stuff. Please help. Thank you.

Posted by dwatord26 8 years ago | last reply 8 years ago


laser trip wire?

I need to build a laser security system. I already have an alarm that works by shorting two wires with a trigger switch there by activating the alarm. I want to activate this alarm with a laser trip wire. I don't want to get a whole security system I just want to get the laser emitter and the receiver. I can't find this part any where. If somebody could help me find this part I would apreciate it. Thanks.

Asked by nurdee1 6 years ago | last reply 5 years ago


Transistors are best for melting brains!!

I have been experimenting with transistors for 3 days now, both NPN and PNP. So far I have concluded nothing. I figure the easiest thing to do is to make a transistor work as a switch. With the NPN, the current seems to flow from the base to the emitter automatically. My understanding is that current should flow from the collector + to the emitter- only when I apply voltage +? to the base, is that correct? I don’t even need to connect the collector on the NPN and current flows. I have also read a million things about transistors online. My experiments seem to disprove most(all?) of the findings. This leads me to one conclusion. I’m not doing something right. Maybe I don’t have the right transistors. I have no idea. I have been using radioshack NPN’s (276-2016) and PNP’s (276-1604) When it tried to make a switch with a PNP my voltages was going back through my emitter to ground. If I disconnected it the system(test led) no longer worked. You might need to know that I was using a 5v voltage regulator to supply a 10v 5v and ground leads for my experiments. I was getting odd voltage readings on my circuits so I put diodes on the leads. The diodes stopped my PNP from working(I figured the current was flowing odd ways…back in the 5v+?) and didn’t seem to effect my NPN experiments. So I figure I’m closer on my NPN’s than my PNP’s. I wish I could explain better but my brain is about to melt. My wife is mad at me because I am obsessed with making this work… please help :P

Posted by kendallickes 9 years ago | last reply 9 years ago


Is it possible to drive a tip31 from the signal generated from an mp3 player? Answered

I have been reading through the many many instructables about driving leds from an audio signal, but so far my experiments  have not worked out.  I'm trying to drive one led from the audio signal coming from a pair of earbud style headphones. Here are some videos demonstrating the circuit. (I can't get the editor to embed videos today, so please follow the links to view the youtube videos Proof that the led works Proof that the transistor works Hooking up the audio signal - I got nothin Proof that there is an audio signal coming into the circuit I'm basing this circuit on the numerous diagrams on instructables for syncing an led to music.  Here are just a couple of them... Sync LED to music LED Music Sync Headphones These and many other instructables show the same circuit and they all seem to be working, so what am I doing wrong? I hooked the base of the transistor up to the signal coming from one half of a earbud type headphone wire, hooked the ground of said wire to the emitter, and then hooked up the collector/emitter to a circuit with one standard led and 3V worth of batteries.  I checked the output of the headphone wire with an oscilloscope, and there is definitely audio coming out of it, but it's a very tiny signal, on the order of a few millivolts.  How does such a small audio signal generate enough sound to be heard?  How does anybody drive a transistor off such a tiny signal?   Doesn't it need at leat 0.7 volts to get over the diodey hump of the base-emitter junction. ( I don't know, that was a pidooma, it's been way too long since my last electronics class. ) thanks for any thoughts...

Asked by foobear 7 years ago | last reply 7 years ago


Can you wire IR devices together? Answered

Can you wire ir devices together?  I'm not sure how exactly IR emitters/transceivers works but if you connect the line going to the IR component directly to the line in the other IR component in the other device, would you have a fully functioning wired connection?  This is for something simple, below the tech of your normal tv remote, like a dollarstore rc car.

Asked by stalledaction 8 years ago | last reply 8 years ago


Does an LED driver rated @ 6v -12v hold/keep a source voltage of 8.4v to 6v or just maintain it between 6v - 12v

I should preface my inquiry with an admission of possessing very limited electronics knowledge. but I am somewhat familiar with battery voltages & amps. I have several Luminus SST-50 & SST-90 LED emitters. I have found that to achieve the full lumen potential these emitters must be driven beyond Luninus's stated typical vf of 3.2 volts. I do not exceed 6vf. I am aware that current is a major factor in the performance of these lights, but when using 5-6amps or the max of 9amps (SST-90)I notice little difference in the brilliance of the light. However, when altering the vf from 3.2v or 4.5v to 6v the difference is amazing. When using 5 X NIMH batteries (= 6volts/4.5amps) with an SST-90 the lumens are high. When I use 4 X NIMH bat @ 4.8 volts/4.5amps, there is about a 25% reduction in light production. With my limited electronics info.I assumed the voltage was the key force here. Or is there something about the volt/current relationships that I need to know? My ? actually concerns the drivers that I have. They are rated @ 6v - 12 v. Do you know if a driver, with these specs, regulates/holds the vf @ 6 volts when the source voltage is greater than 6 volts or does it just maintain the voltage within the range of 6v - 12v. Using 2 X 4.2v LIon batteries, connected to the driver, gives an 8,4v the volt meter reading. Such a voltage will destroy the emitters. I expected a reading of 6vf (@ the driver leads). If you are able to answer my question, one I would be profoundly grateful, 2 please be as detailed/specific/simple as possible. Thank you very much cgc210

Asked by cgc210 6 years ago | last reply 6 years ago


How can I make a remote control for my stereo?

I have a stereo and I want to make a remote to switch between the 6 preset channels on the radio.  I'm thinking infrared because I'll be very close to it and it's simpler than RF.  I have no problem with opening it up or soldering.  I need to know how to make it switch 6 different things, though, with just one emitter/detector pair. Thanks in advance.

Asked by jules15 8 years ago | last reply 8 years ago


Palm Universal Wireless Keyboard disassembly?

I'm toying with the thought of adapting my Palm Universal Wireless Keyboard to work with Bluetooth.  Currently, it sends irDA data at 9600 baud.  This should be decodable using an xmega's usart which has an irDA mode.  One could even bypass the IR emitter, as there are exposed contacts in the base where one can catch the signals prior to irDA transmission (at 1.5V high  / 0.5V low levels). My question is: Does anyone know how to disassemble the keyboard?  I don't see any screws anywhere.

Posted by arpruss 4 years ago | last reply 4 years ago


How many amps do i need to power two LED Cob 9v bars ? Answered

I was wondering how many amps would these two LED bars need in order to work if connected in series, and would a regular 9V battery be enough to power them ? http://www.dx.com/p/high-power-3w-7000k-200lm-white-led-puri-chip-emitter-metal-strip-12-14v-65783#.VgrNC9RXeK1 What kind of battery should i use if a 9v isnt enough ?

Asked by TarikS5 3 years ago | last reply 3 years ago


Basic circuitry help? [not yet resolved]

(I wasn't sure if this should be a comment on the Instructable or not, as it is a bit long, and I have some pictures..) I am following a sound-reactive LE 1.D tutorial and having a bit of trouble. The circuit consists of a SPDT switch, resistor, LED, transistor, and a 3.5mm stereo jack. When I play music using this stereo jack, I get no response from the LED. I'm trying to make something on a breadboard for the first time, so I'm thinking maybe I'm missing something because of that. Here's how the machine is supposed to work: - Positive charge flows to SPDT switch, and if it's in the correct state, continues to the 150 ohm resistor - Anode of LED is connected to the resistor, and the cathode is connected to the "emitter" lead of a TIP31 transistor ("base" is wired to the power bus) - The "collector" lead of the transistor is attached to one of the outputs on the stereo jack - The ground wire on the stereo jack returns to the common lead of the SPDT switch. Perhaps I wired something wrong? I've included pictures if the description is not sufficient. EDIT: I've modified the circuit a bit - maybe I can take pictures / draw a diagram tomorrow. Now, here's how it works: - Positive charge flows from positive side of the power bus to the "base" lead of the transistor - Collector lead of the transistor is connected to the left-channel lead of the stereo jack (also, the ground pin of the stereo jack is connected to the negative side of the power bus) - Emitter lead of the transistor is connected to a 150-ohm resistor - Resistor is connected in series with two LEDs - The cathode lead of the second LED returns to the negative lead of the power bus The LEDs do turn on now, but that's the problem - they are always at full brightness no matter the volume of the music. Even if no music is playing, the LEDs are fully lit. I've used a multimeter to check what's happening, and after pressing the negative lead of the multimeter to the cathode lead, and the positive lead to the anode lead, it shows a constant voltage of 1.986 V. I don't understand how this isn't working - I've verified that the collector lead is correctly connected to the left-channel wire... maybe I should try the right channel? Or a different cable? tl;dr: Rewired and the LEDs are always at full brightness. Transistor doesn't seem to be affecting the emitter output, for some reason..

Posted by hansengel 9 years ago | last reply 9 years ago