Fuse led reset function

[Tinkerer12]

Hello all.. Hope everyone is having a good day..

I have a fuse on a heater circuit and just for fun/knowledge though it would be neat if I add some additional functions to it..
But I can't seem to figure out how to do that and hopefully just keep with simple components (transistors/resistors/caps,etc....)

If my heater is attached and no fuse I get a red LED but I would like somehow insert the good fuse and if I removed it within 5 seconds or something the red LED would be disabled..
If I put the fuse back in and left it for longer than some time period then it would function as normal and if the fuse blows I see the red LED again..
Can anyone show me how I could do that? thanks

So basically anytime the fuse is inserted for less than a set time limit the red led is disabled until a fuse is inserted and left for longer..

Thanks in advance for any help I might receive..

 

[KlausST]

Hi,

The green one will be OK - when you disconnect D1 and the red LED.

When the fuse blows, all the voltage will be across the fuse. Thus you could connect the red LED with series resistor across the fuse.

Klaus

 

[Tinkerer12]

Hi,

The green one will be OK - when you disconnect D1 and the red LED.

When the fuse blows, all the voltage will be across the fuse. Thus you could connect the red LED with series resistor across the fuse.

Klaus

Not sure I follow you there Klause..
I was hoping someone could help me add to the existing circuit so that I could have a way to disable the red LED when I wanted.
The circuit works great as is now in that when the fuse is good the green light is on and when the fuse blows the red light is on..
I would like a way to have some optional functionality for fun so that I could temporarily disable the red LED when I wanted.. (and not just via a boring switch or something)..

 

[d123]

Hi,

"for fun"? That's quirky for a protection circuit... An input device circuit (if a pushbutton is not fun enough) flipping a flipflop which is controlling a Mosfet gate. Fun could be eye or facial recognition, a fingerprint scanner, ...whatever one may dream of but a pushbutton for test purposes, or flip flop + mosfet, is far simpler and keeps component count down and PCB size less large.

 

[Tinkerer12]

Hi,

"for fun"? That's quirky for a protection circuit... An input device circuit (if a pushbutton is not fun enough) flipping a flipflop which is controlling a Mosfet gate. Fun could be eye or facial recognition, a fingerprint scanner, ...whatever one may dream of but a pushbutton for test purposes, or flip flop + mosfet, is far simpler and keeps component count down and PCB size less large.

A push button is something I can already do..
I just wanted to learn a different way to achieve similar results.. learning something new is fun.. I've tried to achieve some sort of latching or flip flop action myself but can't seem to achieve what I wanted..
I just though it would be neat if someone could show how the fuse itself could be used to toggle (flip flop I guess) the working of the red LED or not as needed.

There are times I just use that fuse as an on/off switch to my heater and there are times when I want to keep the heater connected but not have a fuse in place so its not on but also not have that RED led glowing at me..

 

[d123]

Hi,

learning something new is fun..

Agreed, indeed.

Didn't see you'd answered last night, my apologies.

Let's go by stages, please.

Is the fuse a little glass fuse or a switch? Your description is confusing for me, a fuse is not a switch in my experience, unless you're talking about a DC equivalent of an automatic switch, as in an AC distribution box.

Next, to paraphrase SunnySkyguy: "...good specs (or forget it)..."

We want:
#1) Fuse < 5 seconds = red LED off
#2) Fuse > 5 seconds = red LED on
#3) When fuse blows = red LED on

We only want to use:
Simple analog components.

My analysis so far:
We can't square circles, there is a conflicting state (#2 and #3).

By what you say, maybe an IC or two is acceptable, so maybe (ignoring the conflicting states) - and without thinking too hard - a 555 (+ mosfet or bjt) could be used for the time delay part.
We already have the option of any old flip flop IC to add to our toolkit for flipping. Maybe a DPDT PCB relay could be an alternative or be driven by a flip flop.
Why don't we... add one more LED, an orange one (or red if that's what you have), and use that as your standby LED? - This way we can forget about squaring circles.

Said with kindness and vast experience of "beginner's muddled thinking", I think you want the fuse to achieve a function that is possibly impossible, therefore, I recommend adding a third LED. Correct me if I'm wrong about anything.

My ideas are only suggestions as most roads lead to Rome and mine may not be the best route, to put it that way. Flipflop, counter IC, etc. are an example, they're all the same - in a sense.

Look forward to hearing from you.

 

[d123]

Hi again,

Found something nice for you to play with r.e. the time delay section of your circuit and it uses only discrete components: Transistor Delay

It's from another forum and it's reputable like EDA is, I have posted the link because the variations they propose seem fairly ready-to-go with not much modification, just a little head scratching, perhaps - always a plus.

 

[Tinkerer12]

Hi,
Let's go by stages, please.

Ok.. Let me try again (and I've done some more thinking to functionality has changed "slightly" I guess..)

Fuse is a glass fuse yes...

I think I essentially want 3 stages.
1-Power is initially turned on.. No fuse installed yet.. Load is attached = No LED at all (red or green) on.. (Stage 1- Lets call it Standby State)
2-Power is on... Fuse installed (for longer than delay or whatever)... Load attached = Green LED on (Stage 2 - Lets call it Good State)
3-Power is on.. Fuse blown or removed... Load attached = Red LED on (Stage 3 - Lets call it Fail State)
Now I'd like to be able to temporarily use a good fuse to toggle from the Stage 3 state back to the Stage 1 state but not need to leave the fuse installed.. (maybe just need to insert it for less than 5 seconds or whatever to toggle from stage 3 to stage 1)

There are basically times when I want to leave the fuse out or remove the fuse and not have the RED LED energized...
And I'd like to somehow use a fuse to clear that alarm but have the ability to keep the fuse out so that the load is not energized..

I hope that makes sense.. I think this should be possible...

Oh and yes.. IC's are fine.. I really just didn't want to do it with a switch or involve microprocessors... (those I can do..).. this is me hoping to learn more about the "analog" world of transistor logic and that kind of stuff one goofy project at a time
And again.. Thanks in advance for any help you can provide..

I've seen just about every flip flop/latch/set and reset/timing circuit but the lightbulb in my head just hasn't gone off on how to properly incorporate them...

 

[d123]

Hi,

Oh, I'm not receiving new post emails, not sure why, so I didn't see your last post, sorry, again... I'll look into that notification issue later, it's hardly a life-or-death matter. Anyway, look at this and you'll see that it's not like your last post with the requirements but I did the work so bad luck , don't expect it to be usable for you based on last description of needs, just food for thought as an idea.

I have some reservations about how well this would work in the real world without a little tinkering with component values, despite the simulation results, as much as TINA is painfully truthful. Perhaps more experienced members will understand what I'm getting at and see the doubtful parts, if there are any.





I suspect it may take some time to come up with a suitable solution as I have a lot on my plate at the moment and I'm no expert, to say the least. Glad to help if I can. I'll re-read your last post later today, when I have more free time.

 

[Tinkerer12]

I suspect it may take some time to come up with a suitable solution as I have a lot on my plate at the moment and I'm no expert, to say the least. Glad to help if I can. I'll re-read your last post later today, when I have more free time.

d123,
I appreciate the work put in so far..
I had fun just learning what you did there..
If you (or anyone else) can help get to the goals stated in post #8 I would be very grateful..

 

[d123]

A)Fuse is a glass fuse yes...

B)
1-Power is initially turned on.. No fuse installed yet.. Load is attached = No LED at all (red or green) on.. (Stage 1- Lets call it Standby State)
2-Power is on... Fuse installed (for longer than delay or whatever)... Load attached = Green LED on (Stage 2 - Lets call it Good State)
3-Power is on.. Fuse blown or removed... Load attached = Red LED on (Stage 3 - Lets call it Fail State)


C)
Now I'd like to be able to temporarily use a good fuse to toggle from the Stage 3 state back to the Stage 1 state but not need to leave the fuse installed.. (maybe just need to insert it for less than 5 seconds or whatever to toggle from stage 3 to stage 1)

There are basically times when I want to leave the fuse out or remove the fuse and not have the RED LED energized...
And I'd like to somehow use a fuse to clear that alarm but have the ability to keep the fuse out so that the load is not energized..

--------------------------------------------------------------------------------------------------------------------

I have some confusion.

A) okay, good. How is a glass fuse a switch? And more interestingly (I'm puzzled), how exactly do you put it in and out of a live circuit? Even more interesting for me would be why the need to do so?

B)
1 - Why isn't the fuse in place before switching the heater on?
2 - How do you install that fuse in a live circuit, and again: why? The delay part seems pretty easy from simulating a rudimentary one earlier.
3 - Fine, I understand this part.

C) Okay, I think. With all due respect, I see no point in this feature, to be frank. Surely either the heater is a) switched on and i) operative or ii) it isn't operative due to a fault condition or b) it is switched off.

...........................................................

Could we say you could use something based around:
1) No indicators at power on (fuse absent) (open circuit mode)
2) A green one for power good (fuse present) (heater on)
3) A red one for a fault that after a set time turns off?

- - - Updated - - -

Hi again,

Been thinking through my confusion. I think I see where I am stuck with the concept. I think this circuit may need sequential, not combinational, logic because there are two identical states which are supposed to generate two opposing outcomes (at different times: power up and fault condition) in the same component.

Imagine we have a straight line:

Battery-switch-fuse-circuit (heater and green LED)

Now let's use these junctions to obtain valid high or low signals for combinational logic:

Battery-voltage measurement-switch-voltage measurement-fuse-voltage measurement-circuit


SAME: State 1 (power up):Battery-voltage measurement = HIGH -switch-voltage measurement = HIGH -fuse-voltage measurement = LOW -circuit = NO LED
DIFFERENT: State 2 (heater on):Battery-voltage measurement = HIGH -switch-voltage measurement = HIGH -fuse-voltage measurement = HIGH -circuit = GREEN LED ON
SAME: State 3 (fuse KO):Battery-voltage measurement = HIGH -switch-voltage measurement = HIGH -fuse-voltage measurement = LOW -circuit = RED LED ON

Maybe I'm missing something, I don't see where to tap into signals for e.g. comparators or combinational logic devices that will not be the same all the time during stage 1 and stage 3. I only see sequential as a solution or rethinking the design a little.

Again, why the need to take the fuse in and out? I'm fascinated.

 

[Tinkerer12]

Sorry for the confusion.. There is somewhat of a professional application here that I tried to adjust the details to avoid publicly spilling the beans I guess..

A/B1) The fuse was being used as a switch with no other method to turn off said heater..
They would simply stick the fuse in the holders cap and insert it into the fuse holder circuit as a means of turning that device on/off as needed..

C) There are times when they wanted to have the fuse removed (some maintenance process) but have the red LED disabled for extended periods of time while the "heater" was still hooked up.

This issue is all gone/over but I remembered it and just wanted to use it as a project for my own learning/enjoyment..
I got stuck on how to implement that functionality despite trying myself and came searching for some help..

 

[BradtheRad]

The middle circuit in post #9 is handy because it does not need a 555 timer IC. Values can be adjusted to create a delay of several seconds.

You can try various arrangements, namely by putting the capacitor in the other branch of the bias network, or by putting the load in the collector leg. The result can turn an led On after delay, or Off after delay, etc.

Or use a darlington transistor which turns on with tiny bias current. This allows a smaller value of capacitor.

Also, install a resistor (say 1M) across the capacitor so that it discharges between uses. The aim is to reset the delay function.