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Posts posted by jpp412
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Hey Audio,
Yes it is about 18v according to the DVM. -
I don't think that's the problem - at least based on what I had ordered the 7812 was from TI and I used the pinout on their datasheet. However is there someway I could check it? - short of removing it from the circuit and using separate test circuits?
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CHeck out the post on "electronics chit-chat" forum for a pretty good list.
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I have a problem with a 7812 in a power supply such that the output voltage (measured with a dvm) is only 9.5v.
I at first thought the 7812 was bad so I put a new one in and still getting the same results.
I have a 7805 and 7905 in the same supply that work fine.
Any thoughts? Is is possible that I got a batch of 7812's that are no good? (or perhaps mismarked 7810's)
Thanks in advance.
Joe -
Thanks Audioguru. Your explanation helped alot. I'm going back through their ex apps with this in mind to see if I can make sense of it now.
Thanks again!
Joe -
I'm trying to understand the function of the 339. I have read all of the datasheets (which don't help very much as far as basic understanding) and think that the basic idea is to output high when the + input is > the - input and a low otherwise. Is this the correct basic idea?
Beyond that - when I look at the example datasheets which include application examples - I find that most of the examples elude me in terms of what they will do.
Any help or pointers to resources that I could study would be much appreciated.
Thanks in advance.
Joe -
You can just buy the digital pot - check out digikey.
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Sorry about that.
Here is the link:
http://www.electronics-lab.com/projects/telephone/017/index.html -
I'm trying to figure out the microcontroller program.
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Has anyone built this circuit that could help with my questions?
Also, I noticed another circuit ("8-line telephone intercom") posted by someone else - is that a better design for me to try instead of the link 4+0? -
Hey Austin et al:
I am new to this forum and am interested in building the link4+0 for personal use.
1. However, I am somewhat new/inexperienced with this type of thing. I don't see any identification of the parts required to build. Most of them I can figure out by looking at the previous design but not all of them.
2. Why can't this be used for up to 8 phones?
Any help would be appreciated!
Thanks,
Joe -
Hey Austin et al:
I am new to this forum and am interested in building the link4+0 for personal use.
However, I am somewhat new/inexperienced with this type of thing. I don't see any identification of the parts required to build. Most of them I can figure out by looking at the previous design but not all of them.
Any help would be appreciated!
Thanks,
Joe
lm7812 problem
in Theory articles
Posted
I haven't even connected any load to it yet - the regulators are cool.