Search for lm7805 in Topics


16 volts and a LM7805? Answered

I was wondering I'm making a very tiny project with that requires 5v. I'm using these little 3v batteries (CR2016). If I use like 6 of those and a 5v regulator, approximately how fast will they drain? Is that not a good way to lower the voltage? 

Question by HavocRC    |  last reply


LM7805 voltage regulator output 4 volts?

I have a LM7805 voltage regulator hooked up to a saltwater battery that outputs 16 volts, and the output is either slightly above or below 4. When I wire it to a 9v battery, it outputs a steady 4.98, but still will not power a USB port

Question by D5quar3    |  last reply


Is there a difference between a 7805 regulator and a LM7805? Answered

Lm7805 http://www.sparkfun.com/products/107 7805 http://www.radioshack.com/product/index.jsp?productId=2062599#

Question by Munchys    |  last reply


Powering an Arduino with 9V batteries? Answered

I'm looking at powering my Arduino with 2 9V batteries wired in parallel (2 is optional, but if you think a single 9V battery can power an arduino + 16 LEDs simultaneously for >3 hours, let me know). I have a few different options for linear regulators. LM350 (3A), C33275 (300mA), LM7805 (1A, 5V) - I'm guessing I should use the LM7805 because it's fixed at 5 but I'm not sure. I'm not too electronics-savvy so as much help as you're patient enough to give would really be appreciated!

Question by jonrb    |  last reply


9V battery and LM7805 power a audio AMP failled? Answered

Hi,All I use a 9V battery to pass power through a LM7805 to an arduino pro mini,a MP3 module,it works fine.later i am not satisfied with the low voice of the speaker,then i added an Amplifier module.the AMP module is a PAM8403-5V(could be USB powered),but the speaker produce weird sound.  it seemed the PWR was not enough,so i added an extra 5V supply to the PAM8403 module,this time it sounds fine. But i don't wnat to use two PWR sounces to power them.cause it will be bulky,is the 9v battery OK to power them all?or maybe i should use two LM7805s,one for arduino and MP3 module,and another for the PAM8403 module. The pic attached is the working wiring of the project Please help me with this,Thanks. gada888

Question by gada888    |  last reply


How to create a DC power supply filter? Answered

I am programming a microcontroller, and it worked fine. By this time, the microcontroller is powered by the USB port. After programming, i do some testing, i used LM7805 paired with wall wart as the controller's power supply. When using this power supply, the controller's behavior is a little bit unpredictable. Based on observations, the problem is the ripple in the DC supply. I there a filter method or topology that i can use? Note: simple capacitor filter won't work. i have a frequency counter... it reads 0 Hz at the USB and reads 60 Hz at the LM7805 powered by a wall wart.

Question by codestroy7    |  last reply


Will this circuit work to make a solar powered USB charger? Answered

Would this work? It's supposed to charge both the batteries and whatever is in the USB, and then when there is no light the batteries will charge the USB. IN914 is to prevent battery discharge, LM7805 is to change voltage to 5V. The question mark is for a a resistor i heard you need to bridge the white and green connections so it works on iphones/itouches. Anyone know which it is? Link to better image of circuit: http://i27.tinypic.com/n4xq4x.jpg Using this solar panel: http://www.adafruit.com/index.php?main_page=product_info&cPath;=44&products;_id=262 EDIT: I realized that I need two solar panels in series to get 12V, because 6V won't be enough because the LM7805 takes 2V. Am I right? In that case, wouldn't it make more sense to put the batteries in series with the USB

Question by FireFreek    |  last reply


How to make a constant 5v power supply from 12v battery for 3 no. of 1watt smd led lights?

I have lm7805 voltage regulator, 3 nos. of 1 watt smd led 3 to 3.7v 320ma power of each led. I want to use these 3 led in a parallel circuit. so please tell me the resistor value and capacitor value for making this circuit.

Question by grs_14    |  last reply


I'm using a 5V boost regulator?

To charge a cell phone battery.  BUT maximum current is 200 mA.  That's not enough current I'm assuming, right?  I need a continuous output of 5V but my students are most likely not going to get 5V from a shake charger (neodymium magnets going in and out through a coil of wire) which is why I was going to use a LM7805 but that needs 3 volts more than the output voltage.  Any suggestions??  Thank you!

Question by mckywer    |  last reply


Does anyone have suggestions for the 5v power supply for the 8x8x8 LED cube by Chr? Answered

The step about the 5v psu for the LED cube is confusing, at least to me. Here is the page about https://www.instructables.com/id/Led-Cube-8x8x8/step33/Build-the-controller-Power-terminal-and-filtering/ . At first I was going to use the lm7805 but then it said that they took it out. All the pictures show the original design and I don't understand how they replaced it. Someone in the comments talked about using the lm2575 but I am confused.

Question by Arya42    |  last reply


Solar Charger?

Hello, I am looking to build a solar charger in a 4x3x1.6 inch (or smaller) box to be as portable as possible. My only problem is, I would like to mount the solar cell on the box. However, all solar cells are far too large to fit this box, I plan to use a rechargeable 9v battery for power storage. I was wondering if I can use a 6v solar cell, and still use a standard LM7805 5v Voltage Regulator to drop 6v to 5v, or if someone could find a 2.5x3.5 inch solar cell (9v) online somewhere (for cheap) that would really help (I've looked everywhere...) Thanks.

Question by Tuckoguy    |  last reply


Resistors for a NPN transistor? Answered

In the circuit diagram(which I've uploaded),I intent to use a NPN transistor(BC 547) as a relay.The 9 VDC is stepped down to 5 VDC by a LM7805 and should be the trigger to the transistor,completing a circuit which needs the 9 VDC.The Collector is given the common negative of both the voltages and the trigger gets the positive 5VDC.I need a bit help to calculate R1 and R2.I had used two random resistors previously but the Load got powered by the 9 VDC even before the trigger was applied to the transistor.I figured out that the problem might be related to the resistors used. (I haven't included the caps used at the terminals of the regulator in the schematic)

Question by Adarsh_tronix    |  last reply


Portable,rechargeable mobile charger? Answered

I've come up with a plan to make a potable mobile charger for my galaxy phone with a rechargeable 9 volts battery.My original mobile charger(220 VAC input) says it gives an output of 5VDC at 0.7 amperes and hence I decided to make it with the given ratings.So here's my plan-I'll use a 7805 to regulate the 9VDC from the battery to 5VDC.The 7805 gives a maximum of 1 A output.So here's my question should I use a current regulator(LM317) to limit the current from exceeding 0.7 amps or will the phone's battery draw the sufficient amps from the LM7805?Maybe it might be a good idea to assist the output with a resistor as a safety measure.So,what do you say?

Question by Adarsh_tronix    |  last reply


USB Charger Question...

Ok, I have a (4) AA battery holder which is wired in series so that I get 6V. I was then going to use (3) LM7805 regulators in parallel with heatsinks because a AA battery has approximately 2600mAH and each 7805 is rated @ 1A... I tried using (1) 7805 and it was so hot it burn my finger (BAD!) I'm making this device to power a Motorola V3 Razor. I guess my question is if this will work or not, the more I've been reading the USB standard is 5V @ 500mA... Just because the batteries are rated @ 2600mAH does that mean that they will put out that much power? Or will the phone only draw as much power as it needs? I can't afford to use this phone as a test! Please only respond if you know for sure - someone with an EE degree would be nice ;) Thanks in advance!

Topic by 02gsxr600    |  last reply


running LED strip on ac

So i started working on a new project with RGB LED strips and I needed a power source, I dug around my box full of wall warts and saw one that said 12v 3000mA and thought ''perfect!''. I never hit the wires with my multimeter, just used a spare chunk of led strip to figure out polarity.. Anyway, plugged a line into my strip and into my LM7805 and blew my voltage regulator, only then did I look at the power supply and notice it was 12v AC! So to my question (sorry for the long winded intro) How are my LEDs working with AC power?? I switched the leads and they turn on with either line attached, so its obviously alternating, but how could these turn on at all?

Topic by emikayee    |  last reply


Home automation & Home door sequrity including one android apk file project available ???

Please help me for this project. how will be arduino program code , which pin are connect to apparatus to apparatus. please give me all description step by step this project implimentation. Project planning:-                   1.Home automation & Home door sequrity including one android apk file.                   2. 4 Relay:   1. Blue led light.                                 2. Red  led light.                                 3. White led light for bath room using PIR sensor.(this light switch on/off only using pir sensor,                                            because-wet hand electric shock on switch or, damged mobile display).                                 4. Fan using voltage regulator.                                  note:- light switch on/off & fan switch & voltage regulataor incease/decrease including appk file.                   3.Home squrity switch board on/off may be   a.display board on wall of house.                                                                b. display in android apk file.                   4.when open door with corect srquirty,then photo upload in memory card.if incorect password then a lout of sound.                   5.when fire in house ,alarm using gas sensor. Room temperature, huminity show in display. Apparatues:            A: Led light on/off by mobile app.                  1.ESP8266 Serial Wi-Fi Wireless Transceiver Module for IOT.                  2.Generic(unbranded )4-channel relay control board module with optocoupler, 4 way relay module for arduino                  3.Arduino Uno R3 ATmega328P ATMEGA16U2 Compatible with USB Cable.                     or,xcluma Atmel Atmega 2560 Mega2560-16Au (16 Mhz) R3 Board+Usb Cable For Arduino.                  4.Led light 3(Blue,Red,White for Bath room),Motor Fan.                  5.REES52 REES_2 Bread Board or Solderless Pieces Circuit Test Board Project Board.                  6.Jumper Wires Male to Male, male to female, female to female.                  7.Generic KG001 HC-SR501 PIR Sensor Pyroelectric Infrared Module 2pcs(for bath room & door open).                  8.Adraxx LM7805 7508 Positive Voltage Regulator IC, 5V 1A.                  9.Resister 1k ohm.                  10.REES52 MQ2 Arduino Compatible Gas Sensor, Methane, Butane, LPG, Smoke Sensor.           B: Home sequrity.                  1.Quantum QHM495LM 25MP Web Camera.                  2.SanDisk Ultra MicroSDHC 32GB UHS-I Class 10 Memory Card With Adapter.                  3.REES52 621033926893 Universial 16 Key Switch Keypad Keyboard Fit for Arduino by REES52.                  4.Silicon Technolabs 20x4 Line LCD Display With Blue backlight HD44780 for ALL Arduino,Rasp Pi,AVR,ARM,8051 (Blue). Software:      1. Arduino-1.8.5.                2. wampserver & notepad++ (for php web page).                3. Android Apk file.      please help me for this project. how will be arduino program code , which pin are connect to apparatus to apparatus. please give me all description step by step this project implimentation.  i will waiting for you.

Question by somnathpanjaproject2018    |  last reply