Mixing
Logic behind this fuse status indicator
Clash Royale CLAN TAG#URR8PPP
up vote
4
down vote
favorite
I was doing this circuit which I found on the Internet. My question is what is the logic behind the functioning of this circuit?
Thanks!
diodes bjt fuses
edited 18 mins ago
pipe
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
4
down vote
favorite
I was doing this circuit which I found on the Internet. My question is what is the logic behind the functioning of this circuit?
Thanks!
diodes bjt fuses
edited 18 mins ago
pipe
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
7
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
1
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago
add a comment |Â
up vote
4
down vote
favorite
up vote
4
down vote
favorite
I was doing this circuit which I found on the Internet. My question is what is the logic behind the functioning of this circuit?
Thanks!
diodes bjt fuses
edited 18 mins ago
pipe
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I was doing this circuit which I found on the Internet. My question is what is the logic behind the functioning of this circuit?
Thanks!
diodes bjt fuses
diodes bjt fuses
edited 18 mins ago
pipe
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 18 mins ago
pipe
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 18 mins ago
pipe
9,39931951
edited 18 mins ago
pipe
9,39931951
edited 18 mins ago
pipe
9,39931951
9,39931951
asked 4 hours ago
Assprine
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
Assprine
241
asked 4 hours ago
Assprine
241
241
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Assprine is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
7
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
1
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago
add a comment |Â
7
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
1
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago
7
7
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
1
1
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
14
down vote
Q1 and Q2 form a multistable multivibrator which will output a square wave (12V, 0 V, 12 V, 0 V, ...) voltage via D2. If D1 wasn't there then that square wave would turn on/off Q3 and with that also the LED. So the LED would blink.
However D1 is there and via R5 it keeps Q3 on even if the square wave voltage is 0 Volt. So the LED will not blink, it will be on continously.
But there is more. I didn't discuss fuse F1. If that fuse blows (due to overload or short circuit) then there will no longer be 12 V at R5 so R5 and D1 can no longer "overrule" the square wave voltage when it is 0 V. So that means that the LED will blink.
So:
Normal operation, fuse is intact: LED is continuously on
No power at output because the fuse has blown: the LED will blink
Oops, forgot the 3rd state:
When the LED is off, the battery is empty (assuming the circuit and LED are still working).
Sidenote: this circuit uses BC109 which is ancient. It will work just as well with more "modern" NPNs like BC549 or the not so modern but very cheap 2N2222.
answered 4 hours ago
Bimpelrekkie
44.9k24099
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
 |Â
show 1 more comment
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
14
down vote
Q1 and Q2 form a multistable multivibrator which will output a square wave (12V, 0 V, 12 V, 0 V, ...) voltage via D2. If D1 wasn't there then that square wave would turn on/off Q3 and with that also the LED. So the LED would blink.
However D1 is there and via R5 it keeps Q3 on even if the square wave voltage is 0 Volt. So the LED will not blink, it will be on continously.
But there is more. I didn't discuss fuse F1. If that fuse blows (due to overload or short circuit) then there will no longer be 12 V at R5 so R5 and D1 can no longer "overrule" the square wave voltage when it is 0 V. So that means that the LED will blink.
So:
Normal operation, fuse is intact: LED is continuously on
No power at output because the fuse has blown: the LED will blink
Oops, forgot the 3rd state:
When the LED is off, the battery is empty (assuming the circuit and LED are still working).
Sidenote: this circuit uses BC109 which is ancient. It will work just as well with more "modern" NPNs like BC549 or the not so modern but very cheap 2N2222.
answered 4 hours ago
Bimpelrekkie
44.9k24099
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
 |Â
show 1 more comment
up vote
14
down vote
Q1 and Q2 form a multistable multivibrator which will output a square wave (12V, 0 V, 12 V, 0 V, ...) voltage via D2. If D1 wasn't there then that square wave would turn on/off Q3 and with that also the LED. So the LED would blink.
However D1 is there and via R5 it keeps Q3 on even if the square wave voltage is 0 Volt. So the LED will not blink, it will be on continously.
But there is more. I didn't discuss fuse F1. If that fuse blows (due to overload or short circuit) then there will no longer be 12 V at R5 so R5 and D1 can no longer "overrule" the square wave voltage when it is 0 V. So that means that the LED will blink.
So:
Normal operation, fuse is intact: LED is continuously on
No power at output because the fuse has blown: the LED will blink
Oops, forgot the 3rd state:
When the LED is off, the battery is empty (assuming the circuit and LED are still working).
Sidenote: this circuit uses BC109 which is ancient. It will work just as well with more "modern" NPNs like BC549 or the not so modern but very cheap 2N2222.
answered 4 hours ago
Bimpelrekkie
44.9k24099
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
 |Â
show 1 more comment
up vote
14
down vote
up vote
14
down vote
Q1 and Q2 form a multistable multivibrator which will output a square wave (12V, 0 V, 12 V, 0 V, ...) voltage via D2. If D1 wasn't there then that square wave would turn on/off Q3 and with that also the LED. So the LED would blink.
However D1 is there and via R5 it keeps Q3 on even if the square wave voltage is 0 Volt. So the LED will not blink, it will be on continously.
But there is more. I didn't discuss fuse F1. If that fuse blows (due to overload or short circuit) then there will no longer be 12 V at R5 so R5 and D1 can no longer "overrule" the square wave voltage when it is 0 V. So that means that the LED will blink.
So:
Normal operation, fuse is intact: LED is continuously on
No power at output because the fuse has blown: the LED will blink
Oops, forgot the 3rd state:
When the LED is off, the battery is empty (assuming the circuit and LED are still working).
Sidenote: this circuit uses BC109 which is ancient. It will work just as well with more "modern" NPNs like BC549 or the not so modern but very cheap 2N2222.
answered 4 hours ago
Bimpelrekkie
44.9k24099
Q1 and Q2 form a multistable multivibrator which will output a square wave (12V, 0 V, 12 V, 0 V, ...) voltage via D2. If D1 wasn't there then that square wave would turn on/off Q3 and with that also the LED. So the LED would blink.
However D1 is there and via R5 it keeps Q3 on even if the square wave voltage is 0 Volt. So the LED will not blink, it will be on continously.
But there is more. I didn't discuss fuse F1. If that fuse blows (due to overload or short circuit) then there will no longer be 12 V at R5 so R5 and D1 can no longer "overrule" the square wave voltage when it is 0 V. So that means that the LED will blink.
So:
Normal operation, fuse is intact: LED is continuously on
No power at output because the fuse has blown: the LED will blink
Oops, forgot the 3rd state:
When the LED is off, the battery is empty (assuming the circuit and LED are still working).
Sidenote: this circuit uses BC109 which is ancient. It will work just as well with more "modern" NPNs like BC549 or the not so modern but very cheap 2N2222.
answered 4 hours ago
Bimpelrekkie
44.9k24099
edited 2 hours ago
answered 4 hours ago
Bimpelrekkie
44.9k24099
answered 4 hours ago
Bimpelrekkie
44.9k24099
answered 4 hours ago
Bimpelrekkie
44.9k24099
44.9k24099
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
 |Â
show 1 more comment
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
BC109 is newer than 2N2222.
– pipe
2 hours ago
BC109 is newer than 2N2222.
– pipe
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@pipe, I didn't know that. But BC109 is a "metal can" type making it look ancient, it is also expensive. 2N2222 looks more modern in a plastic TO92 housing and also much cheaper.
– Bimpelrekkie
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
@ Bimpelrekkie The original 2N2222 was in metal-can. Plastic was not trusted to be hermetic.
– analogsystemsrf
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
They're all ancient anyway, I doubt it matters much. :)
– pipe
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
I agree, any cheap NPN will do the job.
– Bimpelrekkie
2 hours ago
 |Â
show 1 more comment
Assprine is a new contributor. Be nice, and check out our Code of Conduct.
Assprine is a new contributor. Be nice, and check out our Code of Conduct.
Assprine is a new contributor. Be nice, and check out our Code of Conduct.
Assprine is a new contributor. Be nice, and check out our Code of Conduct.
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7
Do you see the text in the lower-left corner?
– Dave Tweed♦
4 hours ago
I really don't see why there are upvotes. The circuit is so simple anyone could run it through a simulator. It doesn't even take that long to make it, certainly less than waiting for answers. The results speak thousands of words.
– a concerned citizen
53 mins ago
1
@aconcernedcitizen Simulating a circuit doesn't show why a circuit behaves as it does. You can see currents and voltages changing, but it's not obvious why unless you know all the theory.
– pipe
17 mins ago