ULN2003 max input voltage?

[waqqas.qayyum1]

Dear Sir,

Can you please tell me that what could be the maximum voltage we can provide at the input of ULN2003.. Please provide the answer I shall be very thankful to you.

[Andrew F. Ali]

Re: Getting a display from Apricot computer

That is a 7 Channel Hi-Volt Hi-Curr Darlington Array....I couldn't download the Data Sheet.

[budm]

Re: Getting a display from Apricot computer

Dear Sir,

Can you please tell me that what could be the maximum voltage we can provide at the input of ULN2003.. Please provide the answer I shall be very thankful to you.

https://cdn.badcaps-static.com/pdfs/...83d958bacf.pdf

[Andrew F. Ali]

Re: Getting a display from Apricot computer

https://cdn.badcaps-static.com/pdfs/...83d958bacf.pdf

+1..Thanks budm.

[Per Hansson]

Re: ULN2003 max input voltage?

I've deleted your tripleposts in unrelated topics and made this one instead.

Incidentally I saw this video a few weeks ago that takes up this topic:
https://www.youtube.com/watch?v=hkbP...s&spfreload=10

[waqqas.qayyum1]

Re: Getting a display from Apricot computer

Dear Sir,

What is the max voltage we can supply at inputs and supply voltage??

Mean 7 Channel so 7 inputs = What can be the max input volt?

and comm that is supply voltage = what could be max supply volt to this ic?

[eccerr0r]

Re: ULN2003 max input voltage?

Datasheet says max input voltage is 30V.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

Thank you so much sir. Thanks alot.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

I am using ULN2803A for my project. I want to connect 2 relays at each pin. Its mean 8 channel would have 16 relays. So it will work or it will burn the ic? Can any one please give me the answer. I shall be very thankful to you. I am working on this project but I am stucked here.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

I am so confused that 500mA is the max current of all the outputs or its a max current per output pin?

[budm]

Re: ULN2003 max input voltage?

Did you download and look at the spec sheet.
Page 4: 500mA is the max current each Darlington pair can handle BUT the Total current (sink current) is 2.5A (total Emitter-terminal current), so you can have all 7 loads connected to the IC with 350mA per output so you will not exceed the spec of the total current.
Page 5: Vce (sat) is 1.2V @350mA so the power dissipation for each output is 1.2V x 0.350A = 0.42W, times 7 = 2.94W so you must take care of that power dissipation.
You need to use the correct relays that will not draw total excessive current.

[eccerr0r]

Re: ULN2003 max input voltage?

The ULN2803 is 8 channel but also has a 2.5A limit so it can handle even less, worst case, for each pin if each needs to be maxed. At 25°C the max power dissipation of the SMT chip appears to be a bit under 2 watts so depending on your load, the ULN2803 will hit its limit before the ULN2003 because it has one more driver and the somewhat less heat-dissipative SMT18 package versus DIP16.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

Dear sir so can i use 16 relays? 2 relay per channel for ULN2803A. Actually data sheet made me confused. each relay coil resistance is 165 ohm and coil volt is 12V. so can i make operational all of the 16 relays at the same time? is it possible. it will not effect the ic life?

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

Actually sir i want to modify this circuit. The modification is i need to connect 8 parallel relays with the relays on the board. Now total relays will become 16. Actually the relays on board burn mostly and very difficult to change again and again so i need to connect external relays in parallel along with the relays on the board. when the board will turn on the board relays at the same time the external 8 relays will also be turned on so any time if the external relays with base will be burned out i can change easily. so is it possible or ic will be not be effected by dealing with 16 relays at the same time? I am so confused so give me some solution to make this project successful please. I shall be very thankful to you.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

actually i will solder 8 more relays from down side in parallel with the relays on the board. so the relays on board will be dummy or will not take any load. the same new relays will be operation and can be changed at any time in case of any fault. so this modification will work or not?

[eccerr0r]

Re: ULN2003 max input voltage?

Well if you did the math, each relay will draw around 70mA, and 16 of them is well within the 2.5 amperes the ground pin can handle. Calculating it out, you'll dissipate 1.4W worst case, which will make the chip quite warm, and it's probably not a good idea to run that much power through it.

What's the expected duty cycle of the relays, will they most/all be "on" most of the time, or will they be cycled frequently?

I would suggest removing/disconnecting the old relays from the board if you can... that would get around the power dissipation concern during the worst case scenario.

If only one (or in your case, two) relay(s) will be on at any one time, then you don't have to worry about it.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

actually all will not be turned on at the same time. According to this cct 6 relays (for heating elements R N, Y N, B N) will work at the same time. 1 Relay ( inlet solenoid relay for water intake) will work when all the other relays will be off. and the last relay ( drain relay ) will work when the rest all will be off. so external relays if i will add in parallel will work in together with the board relays like 12 relays at a time and 2 relays at a time and 2 relays at a time so it makes total sum of working of 16 relays.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

very difficult to remove the old relays from the board. It damages the board actually

[eccerr0r]

Re: ULN2003 max input voltage?

Also consider how much time the whole device is turned off, but if it's industrial and needs to be operating 24/7 then you can't take this into consideration.

Up to you, take your chances on it, it could go either way. You're best off adding more margin of error to make sure it won't fail (doubling up on the drivers or removing the redundant relays), but at least on day 1 it seems like it should work fine.

And yes the IC will feel quite warm to hot when the 6x2=12 relays are on... which is why I don't know about the long term reliability.

[waqqas.qayyum1]

Re: ULN2003 max input voltage?

Dear sir thank you so much. I try to remove relays from the board. Any how if you know the best idea of removing the relays or how to add other relays by making board relays as redundent so please let me know.