Low AC to DC conversion

Hi, I'm looking for simple way to convert a low AC into a usable DC, of say 4 - 5 volts for charging batteries. I recently saw one discussed online, specced at costing about a quarter, but couldn't find a way to do it, or a way to purchase something like that. Thanks!

Posted by fafnir665 10 years ago


Current Consumtion by a DC Motor?

 I am asking few questions EV related, more current related. Let a consider a dc motor rated 4hp at 24v and 2hp at 12v. So is there a way to calculate ampere draw of the motor at various loads.(like no load, full load, or any load). And if we know the full load current of the dc motor then can we calculate the max load for the dc motor. Next as the dc motor is 2hp at 12v then will this value be constant or will the motor be able to produce 4hp at 12v even rather than at 24v. And will a battery eg 50ah be able to supply more then 50amp.

Posted by flyingdutchmen1659 5 years ago


inrush current make mcb trip

Hi all, i have a problem with my miter saw, it run at 220v and have power 1.8Kw or 1800w my house power can provide 2200Va, the problem is, when i start the miter saw the MCB will trip,  so i must turn off all my electrical home aquipment , than i can use my miter saw. i try to search on g**gle and find that it need some slow start, or soft start so the mcb will not trip again. it cause from inrush current, when the motor start. but the slow start  some forum in indonesia say it can be done by using capacitor bank. to repair the power factor but there is no explanation what size of capacitor bank we can use for any diffrent load...especially a big load like mitter saw for sure, how can i reduce inrush current from the miter saw? what should i do?

Posted by beatobe 6 years ago


USB Power(ed)

I'm obsessed with USB powered gadgets, but i'm not sure what the USB current limitations are, I know that the power output is about 5v,  but i dont know if i can attach gadgets that uses less or more voltaje, so I was wondering if anyone here can give a piece of advice about what can or cant I do with usb power.

Posted by patotec 6 years ago


servos run on 6.5V, but how many amps?

I have five servos running off a picaxe sd21 servo controller and it will operate using four AA batteries, but I want it to run off a wall adaptor. Now theres plenty of adjustable adaptors on the market giving from 3V to 12V and I've seen one that might work for me that can be set to 6.5/ 7.5V, but does anyone know the suitable current range for my device.

Posted by jonnymelon 4 years ago


How to reduce current without reducing voltage

Hi, I'm working on a sign that basically has LEDs as letters. I have 140 LEDs that I'm planning to put in series of 4 each and then 35 in parallel. My problem is that I was mailed a transformer that outputs DC 12v 1.25 A (Actually 12.3V 1.4A). The current is too large for what I need for the LEDs and I don't want them to burn out too quickly so how would I drop the current without affecting the voltage? Any advice would be appreciated, thank you!

Posted by ytan10 4 years ago


Can I Limit Current Without Dropping The Voltage?

This kind of a noob question. I have a power source that supply 12V, 500mA. And the device I'm powering takes 12V, 140mA. How can I drop just the current (from 500mA to 140mA) without dropping the voltage? Since using a resistor would cause the voltage to drop as well. (Right?) Any help is greatly appreciated. Thanks.

Posted by gyromild 10 years ago


12 volt stabilizer/regulator (high current)

Hi, I need something that's able to regulate the car voltage that vary from 10.2 to 14.7 (with lower voltages at startup that's not relevant)  to a stable 12v with a tolerance of 1-2% at high current (need at least 35A but I don't want to full load it too often then 40A would be better). I saw something like a lm317 with some external transistor that's able to put out something like 15A but it required a 30V input and it was a too much low current. can you link me an image of a circuit that's able to do what I want?

Posted by andry08 2 years ago


Best resistor to lower my current?

Hi everyone, I recently started to get into electronics and now need some assistance. I have a 12v and I believe 1A of power. The component I'm connecting is 3.7v with a 450ma battery that uses 3W. I using a l78m05cp, I built what should be a 5v .5A psu, but I must have calculated something wrong because fried my component. I believe the current is what I'm not getting right. Using P=IV, I found I should be using .8A, but I really am not sure about it. Please help, I'll go broke if I keep frying things!

Posted by ramirez_armando 4 years ago


How to select transistor?

Hi guys! How do you know which version of transistor to select when it comes to doing some projects? I mean, lets say i have all the parameters of my project, the output current and voltage, so how do you know which specific model of transistor to select from the data you have? Is there some kind of list from which we can select the required model from our data? For example, i have an LED array which draws about 90mA of current in total and has a total operating voltage of 15V, and from past instructables that i read on this site, i know that BC547 has a current rating of 100mA and can tolerate the voltages, so i can use it. My question is, that suppose i didn't read these instructables, then how will i know which transistor or FET i have to select that has a current rating of about 100mA and can tolerate the voltages(i.e how will i know that i can select the BC547 or alternative)? Also, when selecting a diode for example, i know from reading few instructables that 1n4007 has a rating of about 1A and can tolerate good amount of voltages. Suppose i don't know about the diode, then how will i know that based on my requirements, i can select the 1n4007 diode? This is an example in general, and it applies to all cases of load currents and voltages, and other semiconductor devices.

Posted by charmquark 5 years ago


Practical considerations when using transformer

Hi everybody! I basically love doing LED experiments and i was replacing many of the night lamps and stuff with simple LED circuits i made. Now i have few questions: 1) I generally use transformers to power them (230v/12v). Now apart from primary and secondary voltages and currents, are there any other ratings which i should consider? 2) I have made a portable night lamp with blue LED's. It has 4 arms in parallel and each arm consists of 3 LED's in series. All the arms are connected finally to a single 100 ohm resistor. Now as at most the whole setup might draw about 50mA of current. I had a transformer rated for about  500mA of secondary current, and so i used it with the setup. Will i have any issues using this? (Although i am sure i won't, but just in case anyway) 3)  Also, the transformer gets hot. How much temperature is in safe operating zone? The setup i used, after an hour, got pretty hot. I could barely hold it for a few seconds and i had to let go. Is it okay if it gets that hot?

Posted by charmquark 5 years ago


Circuit Design for DC to DC Buck-Boost Converter

Sir, I am Anand from india, I will made a project based on bicycle. I have take 5 to 80v From my Bicycle pedals. Generator power is in AC 3-Phase. I want to made next step. in this I want to this 3-Phase AC 5 to 80V are constant At 48V DC. I put the 4 batteries in series. 12V 20Ah battery I use. I want to charge this batteries please help me. Thank you.

Posted by AnandC10 2 years ago


Current in IC chip

Hello, It's a bit stupid to ask (I think), but essential to me. From all schematic I readed over intructables I never saw anything or anybody that cared for that. If a IC have a maximum and minimum current to respect ie: 6mA to 10mA, do we even care? Do I need to limit the current somehow? As I said, every schematic I readed never added any resistor or talked about anything relate to limiting the current on the VCC for the integrated circuit. I'm currently building a device that use one 555 timer IC in astable and a few others IC and they are all connected in parralel to the power suply. Thanks

Posted by sxdemon 8 years ago


High Current measurement

I need to measure Current from a welding machine to make a alarm if it goes down below some level for ensuring better quality of welding. The current normally set is of the order of 200A max with around 100V DC.Not sure if i could use some clamp-on meters and pass those values out to Arduino for switching circuit. Shunt resistors may be a better option. But to make a signal conditioner to convert the ma output will be a problem i guess..is there something i can do with Arduino.. any ideas guys....? Thanks in advance Chuppandi

Posted by chuppandi 6 years ago


Too much voltage or will the current limit it?

According to the circuit I need about 6 volts input to run a luxeon star LED. As I understand it, the regulator takes about 3v leaving 3v for the LED and will will provide a fixed current of 320ma which is just fine. My question is, can I use a higher input voltage such as 12v without affecting the luxeon star? Although the current output is fixed, will the output voltage rise as the input voltage rises and burn out the LED?Image reference http://led.linear1.org/a-cheap-current-regulated-luxeon-star-driver-design/1/TIARichard:)

Posted by Richard21 10 years ago


reducing current on a power supply

So I am trying to reduce the on the current power supply I have from an old router. The out put is 12v DC 800mA (.8A). I want to use it to run a man 12v .3AI just wanted to make sure I did my math right and to make sure I didnt miss anything.Ohms LawI = V/RR= V/I V = 12 I = .812/.8 = 15 ohms resistance in theroy_Current on the fan is .3 A, I am assuming that is the max. So desired current is .25I = .25 V = 12 R is current resistance, X is additional resistance Q=(R+X)I = V/QQ= V/IR+X = V/IX = (V/I) - R V = 12 I = .25 R = 15(12/.25) - 15 = 33 ohm resistance neededSo I would need a minimum of 33 ohm resistor. Am I correct?Sorry for the explicitness of the math, its been drilled into me to show every step.

Posted by dragonkeeper117 9 years ago


High Current Power Supply

For a project totally nonrelated to my tesla coil I need a way of regulating a voltage down to 36 Volts at 8 amps. My transformer (or a bunch of transformers hooked together) is suppose to have an output of about 38 volts at 8 amps, yet the voltage (with no load) is actually around 60 volts... Basically I need a way of regulating this voltage. For saftey, lets say the max input is 70 volts and it should be able to handle 10 Amps. The output voltage should be 36.

Posted by guyfrom7up 10 years ago


Current Problems with speakers...

Hey guys, I've uploaded some pictures of my problem. What I have here is an attempt to add bass to my speakers - I'm a newb, so this isn't going so well. The music is comeing from an iDock, and is being routed in parallel to a set of computer speakers. The right speaker has volume & tone knob, the left is simply plugged into the right. I unplugged the left speaker, took the circuitry out, and connected its input & output to a larger bass speaker - quickly was I suprised with a smoking capacitor (lol how healthy!) so... what should I do, simply add a resistor? Edit: Note the resistor (brown red red = 12k? or 1.2k?) is only in series with the LED and is not affecting the bass speaker. I am just wondering how a bass speaker could draw MORE amperage than the small speaker without any circuitry?

Posted by GreenD 8 years ago


How to make a 1-1.5 volt voltage regulator at 15 amps?

Hi, I want to make a high current (15 or 16 amp) voltage regulator that outputs around 1 to 1.5 volts. Does anyone know how this could be done cheaply and easily? I've looked at the 15 amp schematic in the LM338 datasheet (http://www.ti.com/lit/ds/symlink/lm138.pdf  page 11), which uses 3 LM338s in parallel, but I'm pretty sure that takes the minimum output voltage to about 4v, way too much for me. I've looked at using 2n3055 transistor, but it seems like I'd need ridiculous heatsinking and probably fans to avoid thermalling out. I'm thinking of taking my power from an old PSU, 5 v rails, so not too much of a voltage drop, but it's hard to find stuff that can handle these kind of currents. I'm pretty much stumped right now, anyone got any ideas?

Posted by lolkent 6 years ago


What's up with this transformer!

Hey I have a litte problem! (sorta, not yet!) So, I have one of those wall adapter things, and it says it outputs 12vDC and 1 amp. Out of curiosity, i hooked up my volt meter to it and the output was a whoppin 20 volts! Why was it 20 instead of 12 like the transformer said? This is making me worry about my other ones!

Posted by HavocRC 5 years ago


A circuit that turns on randomly

Hey, Another quick questions for the more technically minded than me. I need to make a circuit that turns on randomly between 2 set times. i.e. a circuit that will turn on at a different point between 1 and 3 seconds each turn. I'm hooking it up to a keyboard to stimulate it to press a button, but I think I've that bit sorted! It's getting it to turn on and off randomly that's confusing me. So if any of you geniuses can help!? :D Thanks in advance!

Posted by FreshGarbage 7 years ago


12VDC from computer power supply WHILE COMPUTER IS RUNNING?

Okay, how crazy would this be? I need a 12VDC power supply to do some bench testing. I have a computer by my workbench which has at least one free Molex connector coming out of the PSU. I know I've seen Instructables that show how to make a bench power supply from a disconnected computer PSU, but would it be a really terrible idea to run wires out the back of the computer case to my bench and use them to test circuits? What are the potential pitfalls, and what are some steps I could take to make them less likely? I'm thinking fuses on the incoming power lines are the first step.

Posted by yoyology 6 years ago


Help , electric current from adaptor question

Ok kind of a noob question .. so im running 4 12v dc fans using .28 A current in Parallel with an adaptor that outputs 12V with .3 A current. my question is, will i need to add something (resistor or w/e) to limit the current  so my fans dont fry or will i be ok with nothing?.. i also want the voltage to remain at 12V , because i need them running at full  I searched the forums, couldn't find any specific answer Thanks for your help!! -Chris

Posted by cholborn 6 years ago


Wall outlet current draw

I have built a transformer, that will take 120v, and step it down to 2.5v. I used all the right parts, and the correct rated wire for this. My only issue, is that when i connect the primary coil, to a call outlet, at 120v, it draws more current then my 5A fuse can handle, and the power goes out in my home. I need to get 1.5 amps, @120v going through my primary coil, in order to get the desired output on the secondary. I was wondering, how things "draw" current from the wall, as well as if i where to use a resistor, wouldn't it still draw too much amperage, and just dissipate it in heat, to give the desired output (i cannot use, because it draws more than 5 amps). i could not find a resistor out their, that could handle over 100 watts, so i was also wondering how things like vacuum cleaners only draw a small amount of current. Would i need some sort of current regulator (if that's even a thing)? if you had a light-bulb, and a battery, would the circuit the light-bulb is attached to drain less current, if their was a resistor, and thus having the battery last longer, or would it draw the same amount, and just dissipate energy through the resistor in the form of heat, to give the light-bulb its self less current?

Posted by merlinj 2 years ago


Parts info please

Hi all: Does anyone know of a part that will swith  240v AC current on & off for short periods of time like a pulse effect ?. Thanks.

Posted by tezza1 7 years ago


What's up with Amps, voltage and current?

So I'm having trouble finding out where amps come in. Typical batteries (AAA,AA,9v,3v) don't say the output amps, just output voltage. But things like RC batteries, and wall transformers have a specific amperage output. So say my LED and 9v battery. I know I need to use a 150 ohm resistor. Since resistors limit current, then is there still 9v going to my LED its just the amps/current that being lowered before going into the LED? If resistors limit current, or in its unit of measure, amps, then my LED is still getting the supplied voltage just a lowered amperage?  How do I know how many amps my projects are drawing? How will I know if my DC wall transformer with 12vDC and 1 ma isn't going to fry my circuit? How would I know if 1 amp is too much or not enough for any my circuit? Please help, none of this makes sense, ~electricloser  

Posted by HavocRC 5 years ago


electronic switch

Hi, i'm a bit new to electronics. I was wondering if its possible to turn on the flow of current by another electrical signal. Yes, i know about transistors and relays but these switches turn off as soon as the second current is stopped, how to make this change in switch permanent, i'll be precise, i'm working on a laser alarm system, and it works fine, but the thing is that when i block the laser, sure the buzzer goes off, but when the obstruction is moved, the buzzer turns off, how can this be kept on until turned off manually by a switch. i know it must be quite simple but i dont know, please help thanks

Posted by walee 1 year ago


Limiting power to dc motors

I have 2 dc motors that i will control using an arduino using pwm, my input voltage is 9.6 volts from a battery, but i will use a 5v voltage regulator to power the arduino, the motors are 3v motors. How would i limit the voltage to them using resistors, i have two motors here are their specs Typical operating voltage:  3 V Free-run motor shaft speed @ 3V:  12300 rpm Free-run current @ 3V:  150 mA Stall current @ 3V:  2100 mA Motor shaft stall torque @ 3V:  0.5 oz·in

Posted by tgorbunov 4 years ago


Protecting my new power supply

I've got a 12vdc 500ma power supply that I'm using to trigger a few solid state relays. I'm also using the same power supply to provide input current to a little micro PLC (Automation Direct DL05). Both the relays and the PLC have a wide range of acceptable input voltages and their current requirements are about 15ma per channel at 12 volts. The count is 6 relays and 8 PLC inputs, if all are on thats about 210ma. I once killed a similar power supply by allowing the leads to touch and short-out. I would like to protect this power supply from the same fate by protecting it from short circuit. I thought about attaching a reisistor to the end of one lead and covering all but the outlet of the resistor with heat shrink tubing... problem is, it would have to be a big, bulky power resistor to handle the wattage. Is there a simple component available that will limit the current upon short circuit that I can place in series with my loads to protect the power supply? As I said, it doesn't have to be precise and it doesn't matter if it jerks the voltage around a little.

Posted by fluoronator 10 years ago


Need help changing an AC circuits frequency

Alright, so I have a question about an alternating current circuit I was working on.  The wall outlets I'm drawing power from are AC at 120V, and 60 Hz, but I need it to be 120V at between 60 Hz and 1000 Hz.  A variable system would be nice, but I'm not picky.  How would I do this?  Is my only option to convert the power to DC, and then run it through an inverter?  I would like to be able to do this with a small circuit I could build, something that would fit in a project box.  Any ideas?

Posted by Avren5 7 years ago


LED question

I just bought some LED's that i plan to run through a wire on a 9 volt with a push button on/off i plan to run 6 at a time. the green are 525nm 8000mcd and the blue (A SEPARATE SET) are 472nm 2500mcd

Posted by pbpenguin5 10 years ago


Maximum/minimum ampere input in a circuit, help needed.

To start of my question im going to say i don't know a lot of electronics and that I am norwegian( so please excuse typos in english) :) I have not done many major projects inside the field of electronics other than making a lightbulb light up. using a battery and to wires.. But I am very interseted in electonics ad think it is very exiting to read about.  As my first "real" project i decided to make a "lie detector", altough it is mostly just a circuit that measures the resistance in your skin and makes a beeping sound after how much resistance your skin has( Dry skin = low resistance vs wet/sweaty skin = much resistance). AND I DID IT! i made it work, and i was so proud! Then I realized that it was actually kinda lame and the beebing noise was wery annoying. So I decided to make a display that displayed a value after how much resistance your skin held. I managed to make a seven segment display from scratch. But now I am stuck... You see the circuit gives an output of amps so it will output more amps on wet skin than on dry skin. But I have to "program"  the circuit to make the numbers on my display change. I want preferably to be able to do this without any IC's. So my question is there possible to make a circuit that will allow current to pass through one circuit, but if the current is high enough it will take another way? I tried to use diffrent resistors, but I didnt take into count that electricity only takes the road of least resistance no matter..

Posted by VetleH 3 years ago


pump capacity / electrical interference

I am building a custom watercooling system in a confined space, with the pump motor close to the processor. for the pump, I intend to use a thin centrifugal pump with a centeral brushless motor based around a re-wound cd drive stator, but don't know what the power required to move enough water is, especially with small bore pipe (2 X 1/4" also, when positioning the pump, how far away should it be from the main board to avoid causing interference, as the pump is essentially a large spinning magnet with several amps going to it. I'm guessing the motor should be as far away as possible, as well as the supply cables. thanks for the help.

Posted by The Skinnerz 7 years ago


constant 4.5 V supply using batteries?

how may i get a constant power supply of 4.5 Volt using batteries? -------------------------------------------------------------- WHAT I FOUND SO FAR googling and visiting several discussion groups i found related advice ... - e.g. using 1 more than the required batteries in combination with e.g. a voltage regulator, diode, resistor, DAC - if i use 4 instead of 3 aa batteries and the voltage drops after a while - would a voltage regulator, resistor, DAC still provide 4.5V from the remaining voltage? may i ask you what you would recommend? -------------------------------------------------------------- WHAT I NEED IT FOR i am using rf sender/receiver modules with my picaxe 08m microcontrollers & found, that they (and the connected antennas) work best at a constant voltage of 4.5 V

Posted by marc_is_curious 6 years ago


How to Make a Constant Current Lithium Ion Charger

Hi Guys! I have a bunch of 18650 lithium ion batteries that can handle a charge rate of 5C. Each one is 3,000 milli-amp hours, and I would like to build a charger for them as my project. I understand the mechanics of charging lithium ion batteries, and that they need to be charged at a constant current up until that current reaches 4.2 volts, than switch over to constant voltage. The constant voltage charging makes up about 20% of the battery capacity, and I am willing to forgo that amount. What I am trying to build is a constant current charger for it that would  charge at a current of 1C, and shut off when it reaches 4.2 volts, and I would like some help as to how I would do this. I was thinking that I would have some sort of current source that supplied 3 amps and then have a relay that would shut off the current as soon as a voltage detector reached 4.2. I do not know much about current sources, so I am asking here for some help. Thank You for Your Help!

Posted by merlinj 1 year ago


Electroplate tech used for 3D printing

Obviously it wouldn't work for large scale objects, but could high current, localized "plating" be used to deposit large, controlled amounts of metal to sculpt an object??

Posted by NumbersAndLetters 6 years ago


Looking for some clarity on 1w led power

I am having a hard time working the math and figuring out exactly what I need so I thought a question to others might help. I am trying to determine the best way to power a led light.  Here is what I am trying to accomplish.   I have 12"x12" box that will hold 4 round circuit boards.  Each board has positions for 9 1w leds.  3 for red, 3 for green, and 3 for blue.  Each color is in series.  My goal is to use a 12v power supply for each box.  So we are talking about trying to power 36 1w leds all together but they may or may not be all on at the same time.  The box will be dmx controlled by a computer so that I can adjust the 3 leds in each color on each board.  So its possible that I might only have 1 color on 1 board on for example.  Or I could have one color on all 4 boards on (12 leds) at any given time.  Or they could all be on. My led specs Red (610-630nm):DC Forward Voltage:2.2V~2.6V  Forward Current: 350mA green (510-530nm):DC Forward Voltage:3.2V~3.6V Forward Current: 350mA blue (460-465nm):DC Forward Voltage:3.2V~3.6V Forward Current: 350mA  So a couple things that I am having trouble with.  I know that I can power this with 12v using a high amp (15) source but then I need different resistors with high wattage ratings for different colors I would think?  That seems like a lot of power wasted.  So then I can go with a constant current driver but I can't seem to find one that would apower that many leds at once.  Do I need to do two constant current drivers?  Is there a better way?  and what about the fact that each color on each board may be on or off at various times?  Basically using the dmx controller to colorwash the different corners of the 12 x 12 box.  Will that affect the power drawn and change the supply that I need? Thanks

Posted by joecolafrancesco 4 years ago


Combine 2 powerbanks for mobile

Hello, I have 2 old powerbanks that didn't have enough cappacity. So I want to combine the 2. But both have 5v 800ma output. So if I am afraid that the voltage or the ampere will be to high. How can I combine the 2 without damaging my phone? Sorry for my bad english. Greeting, Thijs

Posted by Thijsd4 2 years ago


Why dont wall transformers have holes?

When i was making my homebrew hot wire for foam cutting, i noticed my 17V low amp transformer ((wall-mount) was getting really hot. So I question to my self, why the heck don't these things have holes? Would it be safe to get a project box from radioshack, Cut out the transformer, and if i want install a fan to keep it cool? or does dust wreck it? Also, theres no way to do hotwires and keep the transformers down right.. i mean its basically a short circuit, as why you try to make the wire hot to cut foam...

Posted by Killa-X 10 years ago


Step down transformer

Hi I would like to build my own power supply. i am a noob at electronics but hopefully this project will improve my skills... http://electronics-lab.com/projects/power/001/index.html This is what I want to build The problem I am not sure on is the 1st initial step of the step down transformer. I have only found a 24 volts 4.16 amps with 100va. I want to keep the project as exact as possible and was currious whether if the current rating is higher than 3 amps for that particular circuit I want to build can it blow any of the circuitry. The transformer I found was 24 volts 100 va and has an output current of 4.16 amps. Is that a problem or will it only draw as much current as needed?  

Posted by Bedawee_zeus 7 years ago


Solar cells in series sum voltage and current?

I am very confused! I built a 10-cell panel (laid out on corrugated plastic for testing). They were rated at 1.8W and .5V. In the sun, putting the volt meter on a SINGLE cell yields about .55 V and 136mA. This is the same for every one I tested, on the panel and individual cells. What the heck? Shouldn't they be about 3.6A? So I soldered 10 in series and put the leads across the final terminals- sure enough I get about 5.5 volts! But I also get about .96A. And current is negative. WHAT THE HECK?! Am I understanding it wrong? I have to be. I thought putting cells in series adds voltage but current is going to be the same as whichever cell is producing the least. Somehow I'm going from .55V/ea to 5.5V/panel. and 136A/ea to .96A/panel. 10 cells. Should have had an 18W panel. Each cell should be giving me 3.6A. "This should be fairly simple" I thought.

Posted by Phoenix17 4 years ago


How to Use Diodes to Harness Mulitple Flows of 4 5 Volts Earth Battery Telluric Current Electricity Generated

Hello, We can generate 4.5 currents using an earth battery in Kpalime, Togo, West Africa. I want to combine 5-10 of these together, and stop the electricity from going both directions using a diode. Do I need a special diodes? How to couple many earth batteries of 4.5 volts together to create higher volts?. I am Andy Lee Graham of HoboTraveler.com http://www.hobotra veler.com/blogger.html  

Posted by hobotraveler 2 years ago


Run AC device on DC: An idea, could it work?

I need to run an AC powered audio mixer on DC current from a battery. Yes, I could buy a power inverter, but I want to make the system the simplest I can, and I also have an old small mixer I'm not using (that I can experiment on). I'm self taught on electronics, so please tell me if there's any inaccuracies in the following lines: My idea is to find where in the circuit AC gets converted into DC, and then at that point feed the DC current from my battery. I think that point would be right after the bridge rectifier. So, in shot: Can I connect de dc output from my baterry to the end of my audio mixer bridge rectifier? Thank you!!

Posted by FrancoMolina 1 year ago


DC power logging, or at least measuring (for solar panel & devices)

I have searched and searched, but I can't seem to find what I need. I want to be able to log power and plot a V-I graph and a P-t graph. I was picturing tapping into an iphone charge cable (for example) and wiring in connections. Here, I could connect the device, so that when i connect the phone via charging usb cable, current runs through the device and is measured, and voltage is read from inlet of the device to gnd. Do these exist? I'd like to also use it for a solar panel (putting a big wire loop resistor for a load to draw max power) so that I could see where the power tops out, what voltage is yielded when the max current is drawn, etc. It would be nice to be able to plot data points in excel for example. Any idea? Even if I can't LOG the data, I'd like to be able to read instant power use, not just V and A. I've seen the inline USB meters that do that. Anything helps! Thank you!

Posted by Phoenix17 4 years ago


Powering electro luminescence wire (EL wire)

I was planning on doing some work with EL wire, but I didn't want to use a battery powered system.  I wanted to be able to plug the whole thing into a wall outlet for power, because I thought that would be nice and convenient and all that, but I had some questions: 1)     Would I need to reduce the voltage of the outlet first?  It's a standard 120 volt outlet. 2)     What components would I need between the outlet and the wire itself to make it work? 3)     What length would of wire could I expect to light with this setup?  What is the limiting factor? I'd appreciate it if anyone could help me.  I haven't ever tried this before, and haven't really explored EL wire before.  Thanks!

Posted by Avren5 7 years ago


What project are you currently working on?

Well, the title says it all, so what are you currently working on?

Posted by starwing123 9 years ago


Buck Converter for Parallel LED's

So I am trying to make a gift for someone that will include about 100 LEDs. These LEDs have a forward voltage of 1.8-2.2 ( I am going with 2V) and a max continuous forward current of 30mA. The LEDs: http://www.ebay.com/itm/50-10mm-10000mcd-LED-Lamp-Ultra-Bright-Red-Light-DIY-New-/180763201504?pt=LH_DefaultDomain_0&hash;=item2a16538fe0 Now, I want to be able to plug this sign into a wall so I have purchased an AC to DC power adapter that plugs in into a standard 120V AC outlet and supplies 12V with 2A of current. Here it is: http://www.ebay.com/itm/261176168283 I know one way I could make this work is to have multiple series of 6 LEDs, as 6 LEDs in a series would then require 12V. However, it would make this project a LOT easier to have all the LEDs in a parallel circuit, so I can connect one whole side to the positive terminal and one whole side to the negative terminal. I wanted to know if I could do this: Plug the two wires (+ and -) going from the AC to DC adaptor into a Buck Converter set to 2V and wire it to all the LED's via one wire to a bus wire connected to all of the LEDs' negative terminals and same for the positive terminals.  The converter I was looking at: http://www.ebay.com/itm/DC-DC-Buck-Converter-Adjustable-Step-Down-Breadboard-Power-Module-1-25V-36V-5A-/321355701600?pt=LH_DefaultDomain_0&hash;=item4ad24add60 Also, if I place the switch in between the AC to DC power adapter and the buck converter, the converter would only be on when the LED's are on, right? Lastly, would all the LEDs have the same brightness? I know at 2V with 100 LEDs the output would need to be about 3A. Is it okay given that the power adapter supplies 2A but at a higher voltage? As in does the converter convert the electricity to a lower voltage but a higher current?

Posted by soulmouse 4 years ago


If an aerial turns EM waves into current...

Can you put current into an aerial and have your own radio generator?

Posted by lewiso1 11 years ago


Which cell & how many do I need??

I'm new to this whole electrical engineering thing. Thx to instructables, I got a crash course in LEDs & wiring them up. I need to make a prototype LED array. How do I determine the right size & qty of cells (9v, AA, etc.) needed to run an array for a decent amount of time for an end consumer? What's the equation for figuring this out? Will the Ohm's Law equation (which I'm new to) work for me here? Anyone's help would be greatly appreciated!

Posted by firesurfer 9 years ago


LED Questions

Help, I'm afflicted with inspiration in quantities that exceed my skills!So I came up with an idea for a project that would probably require the use of LEDs, which I know next to nothing about. Ah, said I, the Internet can teach me much... so I turned here and found the (nearly) perfect Instructable, "LEDs for Beginners":https://www.instructables.com/id/LEDs-for-Beginners/Having read this most helpful I'ble, I certainly came away more knowledge than I'd previously had, but still not enough to properly plan my project.Basically, I'd like to create a 2D "array" of LEDs to use as a light source, in order to backlight a roughly 8.5" x 11" translucent panel.It seems like it would be straightforward to just wire up a bunch of white LEDs in series to a power source and a resistor, and be done. I'm not afraid of a little trial-and-error, but I prefer to know at least roughly what I'm doing going in, so I'm asking for your help. Here are my lingering questions:1. Should I wire my LEDs in series, or in parallel? (Or some combination thereof)? In series, I gather that one LED failing will break the whole circuit, which could be a pain. On the other hand, I've seen several projects and sites that cryptically recommend against wiring these in parallel.2. Are there pre-built strips of LEDs I could acquire that would make this project simpler?3. If I want to vary the brightness of my light source, can I use a variable resistor (potentiometer), or does the nature of the LEDs preclude the use of this type of dimmer switch? If so, could I vary the brightness with multiple switched circuits, turning off half the LEDs for half brightness, 3/4 off for quarter-brightness, etc?4. I've got a slew of transformers from old tape decks, telephones, cell phone chargers, etc. Can I appropriate one of these as my DC power supply?5. How do I gauge how many LEDs I'll need, and what density is best to lay them out? I'm looking to create even, diffuse light, with no noticible bright/dark spots.6. Do I need to worry about heat?7. Are LEDs even the correct way to go here? Should I consider fluorescent light instead?I realize these are a lot of questions, but if you're an expert on LED projects, you could save me a lot of research time. If (I build this gadget, it will definitely show up here as its own Instructable.)Thanks!-JD

Posted by jdtwelve12 9 years ago