The relay installed has a 9V rated coil with a nominal resistance of 225Ω. R18 should be 75Ω if the relay coil is to be driven with the rated voltage and current. It is currently 22Ω (pointing to poor circuit design), so the relay has been driven beyond its rated values. The coil current through 22Ω would be 48mA, so the resistor dissipation should have been 52mW in theory. That would be expected to make the resistor warm, but not hot. If it runs excessively hot, perhaps the coil has shorted turns from being over-driven.
Help me understand a 12V SLA charging circuit.
- Thread starter Buk
- Start date
kellys_eye
- Jun 25, 2010
- 6,512
- Joined
- Jun 25, 2010
- Messages
- 6,512
No, I can't. The Mods can - but I can't.
Once a post has been made after mine, the contents of previous posts are locked and I can't change them. When YOU quote me, YOU can change the content - which you clearly have and used the letter 'O' instead of the number 0 - which makes you worse than a liar.
This thread is degenerating fast - not only have you been abusive you are now calling me a liar. What next? Coming to find me with your gun?
Seriously......
- Joined
- Jan 21, 2010
- Messages
- 25,510
I have been looking at this thread for some time.
I can see no evidence that @kellys_eye or a moderator has edited any posts. (@Buk has edited a few of his posts though)
Edit: @kellys_eye modified one of his posts, but not too change a resistance value.
The author of a post can edit their post for a short time after posting, but I don't see where @Buk has replied so soon after a previous post that it is likely that the post being replied to was being edited at the same time.
My guess is that the post rendered incorrectly. To my eye the image which appears to say 220, actually seems more like 22O. Also, I have not seen @kellys_eye refer to resistor values without an Ω or "ohms". However, I wouldn't assume @Buk would notice the difference between 220 and 22O or the relevance of the missing unit designation.
There is a post somewhere where I showed how to reverse engineer a simple circuit, including getting it into a conventional form. If @Buk is interested I'll try to find it. The process is not simple, and is not something I would do for fun. Edit: look here.
I am inclined to close this thread, but at the moment I'll give @Buk time to reconsider whether he wants to wind back time a few posts and start again.
I can see no evidence that @kellys_eye or a moderator has edited any posts. (@Buk has edited a few of his posts though)
Edit: @kellys_eye modified one of his posts, but not too change a resistance value.
The author of a post can edit their post for a short time after posting, but I don't see where @Buk has replied so soon after a previous post that it is likely that the post being replied to was being edited at the same time.
My guess is that the post rendered incorrectly. To my eye the image which appears to say 220, actually seems more like 22O. Also, I have not seen @kellys_eye refer to resistor values without an Ω or "ohms". However, I wouldn't assume @Buk would notice the difference between 220 and 22O or the relevance of the missing unit designation.
There is a post somewhere where I showed how to reverse engineer a simple circuit, including getting it into a conventional form. If @Buk is interested I'll try to find it. The process is not simple, and is not something I would do for fun. Edit: look here.
I am inclined to close this thread, but at the moment I'll give @Buk time to reconsider whether he wants to wind back time a few posts and start again.
Last edited:
No shit Sherlock! Wadda'y'know, a self-identify beginner misinterpreted a datasheet.
Just a shame it took 2 days and a dozen posts here, and then going somewhere else before that could be identified (here).
All the information (including my misunderstanding) was available in simulation I posted in my OP. And was identified immediately by (several) guys at the other place, who don't have their heads up their arses.
- Joined
- Jan 21, 2010
- Messages
- 25,510
Not necessarily. At 48mA the relay has 10.8V across it. The spec allows up to 130% of the nominal voltage (9V in this case), so anything up to 11.4V would be within the specified limits.
Agreed, but why deliberately design something to run at higher than rated values (unless, of course, this is to ensure the unit fails just outside the warranty period
) ? Perhaps a 22Ω resistor was cheaper than a 75Ω one .
Gentlemen, please moderate your language. Insults will not help to solve the problem.
I would like to know
1. How this circuit works, the schematic seems to be almost there. I know I could not get this far.
2. Where this other electronics forum can be found.
I would like to know
1. How this circuit works, the schematic seems to be almost there. I know I could not get this far.
2. Where this other electronics forum can be found.
kellys_eye
- Jun 25, 2010
- 6,512
- Joined
- Jun 25, 2010
- Messages
- 6,512
There are quite a few issues needed to be resolved in order to give the OP the answers required.
Without the proper schematic you can neither give an accurate statement of how the circuit works and nor will any simulation software work correctly i.e. garbage in, garbage out.
One area (the relay and resistor) has been resolved but the OP seems to have been given misleading information by 'the other forum' regarding the relay itself (operating voltage, coil resistance etc).
Sad to see that the responses to legitimate answers (or requests for more input) turned to abuse - there was no need for this and deliberately editing posts to make me out to be a liar - as the OP tried to cover his own mistakes - is beyond belief....
All that was required was a little more work from the OP to develop the schematic into something that worked - but he/she seemed to think that was 'my' task and seemed disgruntled that I requested that he/she should be required to do so
No real point in keeping the thread open imho.
Without the proper schematic you can neither give an accurate statement of how the circuit works and nor will any simulation software work correctly i.e. garbage in, garbage out.
One area (the relay and resistor) has been resolved but the OP seems to have been given misleading information by 'the other forum' regarding the relay itself (operating voltage, coil resistance etc).
Sad to see that the responses to legitimate answers (or requests for more input) turned to abuse - there was no need for this and deliberately editing posts to make me out to be a liar - as the OP tried to cover his own mistakes - is beyond belief....
All that was required was a little more work from the OP to develop the schematic into something that worked - but he/she seemed to think that was 'my' task and seemed disgruntled that I requested that he/she should be required to do so
No real point in keeping the thread open imho.
Similar threads
