179 Threads found on edaboard.com: uln2803
Please specify that where can I find serial uln2803 type ICs?(with short circuit protected output power transistors,if possible)
Professional Hardware and Electronics Design :: 07-18-2003 13:30 :: 7rots51 :: Replies: 5 :: Views: 1889
I've been used it very times.
And I want find a inverting of uln2803
- uln2803 is NPN darlington.
- I find PNP darlington
Seem I post wrong topic. Sorry
Hobby Circuits and Small Projects Problems :: 09-08-2004 04:32 :: conkhicon :: Replies: 1 :: Views: 1418
i have 2 boards
2.74HC595 -> uln2803
the connection is 2-3m /~5ft/ the system is work good but in one moment stop, i put a control LED on one of the ports to seen is the controller work . the controller work but no reaction on other board
may be the problem is in cable or signal level :((( can some help me
Microcontrollers :: 08-12-2006 08:28 :: syrax :: Replies: 1 :: Views: 2463
i would suggest uln2803, coz it contains 8 current drivers so overall u'll need 2 uln to for this. Most of the 8x8 LED arrays will have 16 pins( 8 anode connection and 8 cathode connection) by giving proper signal u can glow a particular LED.
Buffer must be placed between ULN and controller in order to protect the controller. By giving correspondi
Electronic Elementary Questions :: 02-12-2007 07:21 :: brahma :: Replies: 2 :: Views: 4045
I'm making a stepper driver with uln2803. It's working, but the IC heats up very quickly. I'm not using microstepping. I'm using two outputs paralleld together, totaling one ULN IC per driver (8 outputs / 2 = 4 outputs, as needed for uniploar driving).
Is it safe to operate the ULN in high temps?Or should I get some cooling? Is there cooling for
Hobby Circuits and Small Projects Problems :: 09-26-2007 17:08 :: izua :: Replies: 3 :: Views: 2511
I think I must connect Vcc=5 Volt on the Common pin, that is Pin number 10.I don't understand the concept of diode as shown in the diagram. It seems like as if it's working like a pull up resistor. I also don't understand the other two diodes drawn in a dashed lines (- - - - -). By studying various other examples on uln2803, I hope to learn how thi
Microcontrollers :: 07-13-2008 11:56 :: umery2k75 :: Replies: 11 :: Views: 17118
In my design,I try to use AT89S52+uln2803 for Led driver.Could I connect port 1(or 2,3) to 2803 without any pull-up resistors?
Someone said port1(or 2,3) can not output 1mA current.But I can not find the parameters on the datasheet.
Professional Hardware and Electronics Design :: 07-15-2008 03:24 :: dwep :: Replies: 3 :: Views: 5017
i am working on uln2803 to drive my DC is supposed to get an inverted o/p at its o/p pin i.e When I am giving an logic low input i must get an logic high output...but my outpin pin is always giving an low signal irrespective of my i/p signal.I have pulled up all my inputs.Please help me to find a soln 2 this probl
Microcontrollers :: 10-22-2008 10:02 :: vikky :: Replies: 6 :: Views: 1509
have you guys tried using uln2803 as driver for 74LS595 for use in LED matrix
what do you want to ask??? your desire is not so clear?????????/
Microcontrollers :: 02-20-2009 15:26 :: sn_burki :: Replies: 5 :: Views: 3287
Hi, anyone can help me how to use uln2803 to drive Relay.
I use uln2803A and my coil relay is 12VDC. COM on the pin no 9 should be connected to 12v or 5v? and uln2803 doesn't have VCC pin.
Please help me if possible in a diagram.
Microcontrollers :: 08-16-2009 05:36 :: philips1983 :: Replies: 1 :: Views: 6757
From My SBC Board supply of +3v is coming and External Device need 12votl supply can I use uln2803 between board and device as a Voltage convertor??
Hobby Circuits and Small Projects Problems :: 08-20-2009 02:00 :: dinesh.4126 :: Replies: 16 :: Views: 7565
I have a pcb which is using pic16f72 and uln2803 for stepper motor control. I need a program for this circuit and schematic. Can anyone help me please. I searched over net but i could not able to find
Actually i have bunch of (10 to 15) steppers from old printers, i want to test them and use it for robotics. So i can use this circuit
Microcontrollers :: 12-05-2009 13:22 :: imported_robotsmani :: Replies: 0 :: Views: 1209
the gnd pin of this chip uln2803
can i ignore it or hook it to the gnd?
in proteus, this chip has no such pin
i wonder in real circuit if i should connect it to the ground.
Microcontrollers :: 01-14-2010 04:14 :: newbie111 :: Replies: 3 :: Views: 797
Some suggestions about your schematic design :
Use uln2803 output in open colector the LED with your relay.
PCB Routing Schematic Layout software and Simulation :: 05-31-2010 13:31 :: sokrad :: Replies: 2 :: Views: 13241
I needed help on using uln2803. Like i wanted to drive some relays using uln2803. So how should i configure the uln.
The condition is i want to ouput 12 from uln2803. I have provided ground to 9th pin and 12vcc to 10th pin. Now if i provide ground from microcontroller circuit. to input pins (i have shorted the ground from microcontroller (...)
Analog Circuit Design :: 05-10-2011 07:43 :: prathyks :: Replies: 3 :: Views: 1458
I would like to ask some questions about the uln2803 device.
I am working on a college project and i need to interface some 5V signals with a PLC which requires a input voltage of 12 V.
Can i use a uln2803 for that? Can anyone explain me how to build a circuit to interface those components??
thansk a lot
Hobby Circuits and Small Projects Problems :: 07-25-2011 14:18 :: alimary15 :: Replies: 4 :: Views: 2586
how can i connect the output of IR Receiver to input of p89v51rd2 microcontroller and output of microcontroller to drive a uln2803.if i connect output of ir receiver(4.94v)directly to my microcontroller pin,will my microcontroller work?
and one more thing,can i connect microcontroller output directly to uln2803
Electronic Elementary Questions :: 11-06-2011 13:57 :: navneet sngh :: Replies: 8 :: Views: 1259
This project may help a new hobbyist to understand how to interface uln2803 with PIC micro to control loads up to 500mA with schematic, picture and video.
Please refer to uln2803 datasheet at
Here the given code will drive 8 lines of LEDs to produce few fascinating designs.
Microcontrollers :: 11-20-2011 03:25 :: papunblg :: Replies: 2 :: Views: 1354
My question is can we stack two or more uln2803 ICs on top of each other(i.e. in parallel) to increase the max current capability? I want around 600mA in each of the 8 channels at 50% duty cycle (to drive two steppers in full step mode).
Thanks in advance!
Analog Circuit Design :: 12-30-2011 04:46 :: robert576 :: Replies: 1 :: Views: 412
Hi i want to use a pic microcontroller to control an array of 50 leds. I'm using two uln2803 ICs to control the anode and cathode of the leds but
i'm having problems with my schematic because uln2803 is a NPN transistor array and i can only sink the voltage and not supply it. Is there any PNP array
Microcontrollers :: 12-31-2011 12:41 :: georgz :: Replies: 7 :: Views: 1348
Your schematic lacks sufficient detail.
The following is an example Relay to uln2803
I have also attached a PDF for a 4 Relay Board using a uln2803 which has a schematic.
Professional Hardware and Electronics Design :: 04-21-2012 01:25 :: bigdogguru :: Replies: 7 :: Views: 3841
can i use a uln2803 (50V, 500mA per channel) to drive a 1.5A per phase stepper motor without load ?
Power Electronics :: 09-06-2012 12:31 :: varunme :: Replies: 3 :: Views: 579
I have used UDN2981 in my project to drive 4 seven segment displays, 2 big LED's & 1 buzzer. The Vs pin(9) is connected to 5V supply of micro-controller. Resistors for displays & LED's are chosen accordingly.
Now my problem is that the sound from buzzer is not enough on field. I will have to increase the supply of the buzzer (it can work from 3V
Professional Hardware and Electronics Design :: 09-20-2012 04:44 :: vbdev :: Replies: 2 :: Views: 1080
NO ! you cannot use a uln2803 for controlling a mains triac there is no isolation, use a proper opto isolator, many circuits around.
Microcontrollers :: 12-12-2012 04:40 :: wp100 :: Replies: 1 :: Views: 479
Connect input drive signal to uln2803 input pin. Connect lamp between the corresponding output pin and +V. Connect pin 10 (COM) to +V. In Proteus, the common emitter pin of uln2803 is hidden and is connected to ground.
By the way, for driving a single lamp, you can just use a transistor. You don't need to use uln2803.
Hope this helps.
Microcontrollers :: 12-14-2012 07:01 :: Tahmid :: Replies: 3 :: Views: 936
I have to ask that how can we make uln2803 output high if respective input is high? Is there any way?
Secondly If I make common high, then if input of some PIN is high then output of that respective PIN goes LOW and all others remain in high impedence state, I want to eleiminate this high impedence state and I want only hig
Analog Circuit Design :: 03-28-2013 03:32 :: assadmahmood :: Replies: 2 :: Views: 532
can u help me to choose my driver to control a unipolar stepper motor. wath is the best choice, uln2003A or uln2803 ???
Microcontrollers :: 04-20-2013 17:09 :: Tiabak :: Replies: 1 :: Views: 265
uln2803 is a darlington driver. It can't achieve 0.1 to 0.2 V saturation voltage.
Analog Circuit Design :: 06-12-2013 08:26 :: FvM :: Replies: 3 :: Views: 258
Hello there ,can you please help me to drive those dot matrix by proving a drive uln2803 bebween the 74LS138 and DOT MATRIX.
I tried to do that but I failed.Please help.
without the drive the circuit operates very well in simulation but on the board with physical implementation;it doesn't work,I just see some column shifting.
See my project
Microcontrollers :: 09-01-2013 14:59 :: jean12 :: Replies: 9 :: Views: 773
As I promised I made and uploaded a project, just as you wished: it uses a PIC16F876A, three 8x8 LED matrices, a 4017 (instead of LS138) with uln2803, and three HC164 (instead of HC595). There are also a Start-Stop switch (see the DSN).
Note this is a Proteus-only project, I hope it works also in the reality, try it. But do
Microcontrollers :: 09-10-2013 14:45 :: zuisti :: Replies: 22 :: Views: 1541
Heyy i am driving 4inch 7 segment common anode display using 89S52 & uln2803 !!
normally my circuit works perfectly ,,but whenever i touch any pin of uln2803(which is used for driving 7 segment display) with my multimeter's probe, the respective segment switches off !! ??? & this happen with every other segment when i touch respective pin of
Microcontrollers :: 09-27-2013 04:54 :: kunaltg :: Replies: 11 :: Views: 611
i tried and get something wrong with uln2803 i test all the way but i am failed . and last i remove one by one part and replacing uln2803 with hcf40106 result got fine . so i tried again and inform u.
Microcontrollers :: 10-17-2013 01:26 :: nick703 :: Replies: 12 :: Views: 339
I am busy building the following: .
I appear to have a problem driving the uln2803A with the PWM controlled FET (IRF520)... or with the uln2803A being driven by a PWM controlled FET...
I currently have 7 LEDs wired to the uln2803 outputs, resistors wired to ULN out
Hobby Circuits and Small Projects Problems :: 03-03-2014 05:33 :: neillsun :: Replies: 16 :: Views: 819
You can use ULN2003 or uln2803
Professional Hardware and Electronics Design :: 06-06-2002 17:19 :: 7rots51 :: Replies: 15 :: Views: 8545
use the old tl084
it has 4 op amps and works rail to rail on 5 volts
just divide your input voltage. you may add filtering also.
For signaling i normaly use a uln2803 with a diode to
sense on/off inputs
Professional Hardware and Electronics Design :: 06-13-2002 20:23 :: padspcb :: Replies: 12 :: Views: 2490
I have used 89c2O51 for this purpose. The port 1 drives the segments through a uln2803 (or ULN2003 if no decmal point is needed). For driving teh digits, I use 3x74LS138 and BC557 transistors. I think this is the cheapest solution that can be made for this purpose.
Professional Hardware and Electronics Design :: 12-22-2002 10:20 :: techie :: Replies: 16 :: Views: 2421
I want to replace a Siemens PLC by a microcontroler. For the 24V output I'll use some classic drivers like uln2803.
Can somebody give me some tips and/or diagram to obtain the same reliability as professional PLC.
What kind of components I have to use to proctect for example from HVoltage spikes, short circuit, reverse current....
Professional Hardware and Electronics Design :: 02-28-2003 04:00 :: mdamdam :: Replies: 7 :: Views: 1737
My avr micro 8515 on/off a relay by a uln2803 driver,when relay have no load everything goed well,but when I attached a 100w lamp as load to relay contacts the avr resets when turns the lamp OFF.
I used the snubber circuit across contacts but problem remains.
Please guide me.
Analog Circuit Design :: 01-10-2004 13:51 :: 7rots51 :: Replies: 5 :: Views: 2762
I found also a chip to do that
Professional Hardware and Electronics Design :: 04-08-2004 02:53 :: SphinX :: Replies: 5 :: Views: 1074
What is the best way to interface a 3V microcontroller to 15V CMOS ?
is it possible to use uln2803?
Microcontrollers :: 05-25-2004 02:02 :: mystery :: Replies: 7 :: Views: 1391
You can also use such darlington array : = t
Analog Circuit Design :: 08-11-2004 04:11 :: papyaki :: Replies: 2 :: Views: 954
Great. Why dont use the power supply from the printer itself? Also, u can try uln2803 type of things instead of transitors.
Hobby Circuits and Small Projects Problems :: 09-09-2004 04:48 :: asit :: Replies: 6 :: Views: 1035
I am a total newbie in HDL :oops:
But now i might have a thing where a CPLD could come in handy
I have gotten some 8x8 LED blocks Red/Green (See attached DS)
And i would like to build a display with 8 of those blocks , and control them with an Atmel Mega16 or Mega32.
Each 8x8 block have 24 pins so its 8 x 24 pins in all.
PLD, SPLD, GAL, CPLD, FPGA Design :: 12-17-2004 14:30 :: Bingo600 :: Replies: 1 :: Views: 990
as far as I remember the 8051 has a weak pull-up current source of about 100uA at his ports. It is not able to drive a uln2803! You will need an external pull-up resistor. The current consumption is to high for more channels.
An external FET is only a solution if it is a logic-level FET ! You need a flyback diode.
The best way is to use a intell
Electronic Elementary Questions :: 12-29-2004 09:58 :: felix1200 :: Replies: 14 :: Views: 5324
What is your load ?
Why not use BC337, 2n2222, uln2803, or L293... ?
Professional Hardware and Electronics Design :: 01-25-2005 21:52 :: manu :: Replies: 7 :: Views: 2209
How big is maximum current per pin? In LVTTL it is said +/-24mA minimal. For testing purpose I want to connect LED diodes to FPGA structure, but there is no documented limitation of safe maximal current per pin (it is no so important) and per port (it may be important, because whole current goes thru Vcco pins and ground pins). So is there any limi
PLD, SPLD, GAL, CPLD, FPGA Design :: 02-16-2005 19:05 :: elektryk :: Replies: 2 :: Views: 620
try using uln2803 driver IC , u could use two or after the 2803 u could connect a D313 transistor, capable of driving upto 2Amps.
Microcontrollers :: 11-22-2005 12:03 :: snabilat :: Replies: 9 :: Views: 1112
CD4050B it's not able to provide the requested source current for multiplexed LED display, even if the gates are parallel connected.
You must use either 16 NPN transistors or one uln2803 (as suggested by HUGo, driven by port P1 outputs) and 8 NPN transistors for rows.
and obvious 8 resistors for current limiting (a value of 220R would be fine).
Microcontrollers :: 02-04-2006 18:46 :: silvio :: Replies: 12 :: Views: 3733
Yup - you can create your own schematic parts, PCB footprints and simulation models.
The first two are documented in the help files whilst the latter is in the SDK. You can also request development direct from the Labcenter peripheral modellers provided that the part is general purpose enough to be of use to the customer base.
PCB Routing Schematic Layout software and Simulation :: 07-26-2007 04:36 :: Iain :: Replies: 2 :: Views: 2869
I agree that 2N7000 or BS170 (TO-92) or 2N7002 (SOT-23) make good low current low side switches.
Also consider uln2803 8-bit parallel sinking driver or MIC5841A serial-to-parallel 8-bit sinking drivers.
Good luck. Regards, Mike
Microcontrollers :: 07-17-2006 21:34 :: Mike, K8LH :: Replies: 6 :: Views: 8859