Timer circuit - not working in EC

Put a wire across that pushbutton (that button should not be there). Get rid of the 470 Ohm resistor (it's wasting current). Change the scope time scale to 1s then use your top switch ... work from there.

The push button is perfect as it is. Just leave it. Only thing is the cap size must be adjusted for the simspeed. At 1s/s e.g. 50uF is fine. This is half of a astable multivibrator and shows what happens if the transistor (which is presented by the push button) of the opposite side will get active. Also the 470Ohm is fine cause it simulates the load of the second half of multivibrator. Dont let you confuse and continue on your external link.

Because of some saturation effects i have increased also the 470 to 2kOhm http://everycircuit.com/circuit/5054956171427840

@hurz ... That original link circuit was not saying that it was an unfinished astable multivibrator circuit, it was instead stating that it was a complete working circuit. andyraffle can choose between yours or my alterations ... both are options.

Its and working circuit which you as always do not ubderstand and just messing around.

Take the original circuit and push the button and KEEP IT PUSHED. The resistor you recommend to remove is importante. The button you short circuit is importante. All tipps you gabe are rubbish.

What is you do not understand “this circuit here is a working circuit!“ ?????

@hurz ... andyraffle enquired as to why his copy of the link does not work. The simple answer to that is because he did not copy it correctly... There is no button in the link schematic, there is a switch instead. The newly placed button by andyraffle is also not in the same position. Your suggestion of holding the newly placed button is not therefore helpful. Note also that by doing so, the 470 Ohm resistor loops to the supply and uses many pointless mA in that setup... Various alteration are thus required as per our mentioned options. Here is a clarified view of my mentioned suggested alterations:  http://everycircuit.com/circuit/5336605094313984

What is you do not understand “this circuit here is a working circuit!“ ?????

Ah, and your alteration is shitvand has nothing todo with the external link. Its just @2cent messy action

Again “THIS IS A WORKING CIRCUIT AND DOES NOT NEED ANY MESSY ACTION BY @2CENT“ http://everycircuit.com/circuit/5503971145023488

Your first comment is 1 hour ago. @andyraffle made its last change 2hours ago. @2cent you are a pain in the ass

The usual dickhead hurz who has to be the only one here with opinions, who hates to lose an argument, and who always spoils the EC community with bitter antagonism. We know that it is a working circuit by holding the button... but that is not what was required ... that's why he enquired here.

Thats exactly whats enquired. You seems to be blind for electronic. So look for another hobby

Timer circuit..... no point in making a 1hr timer if you have to hold the button in for 1hr before it comes on... lol.

You continue messing and being nasty, why? Just shutup try to undestand electronic a little

Look back through these comments here and see who started the unpleasant remarks...same as always...you... and as usual, you turn things around to make it look as though the other person started the antagonism... We all know your tricks hurz... you are washed up.

I have tuned nothing. You turned anything by messing as always

Hurz...the new Mr 'hold the button down and achieve nothing but wasted current' ... lol

You are such an idiot. You not even tried to press the button. Press it till the led goes on again and then release the button and we can talk again. Cabron

Then for a 1hr timer....hold the button and waste useless current for that annoying time duration ... The OP presumably wanted something more than holding the button down for an extended time in order to activate his request.... This is not a demonstration of a 'work towards understanding astable multivibrtors'.

If you were to stop calling people 'idiots' when they have viewpoints contrary to yours, then sensible discussions could be performed. You must realise that your own viewpoint is not always going to be valid.... and then be prepared be acknowledge that ... that would give you more credibility.

But you are an idiot and you cant stop

Again and again you talk about waste of current. Thats wrong! This resistor is more its purpose is to discharge the cap after ise. You dont listen. You dont read circuits. You mess foreign circuits to something completely different. Your circuit is by far not an 1 hour timer. You dont want to understand. What is wrong with you?

THIS CIRCUIT HERE AS IT IS, IS A WORKING TIMER CIRCUIT (idiot)

Sad case hurz

Everytime you fail. You fail again and again. You fail and mess foreign circuits. Your circuit is bullshit. This circuit here is perfect! You are a pain in the ass

You think that continuing every argument to ensure that you have the last say makes you the 'winner', but in reality, sensible people decide when to stop rather than pursuing nonsense with a delusional helpless case such as you hurz.

See what a nasty piece of shit you are without any arguments. Go to hell and tell the devil how useless this 470 Ohm and switch is. But dont tell us this bullshit. Idiot

As a Christian (admittedly, a not very good example), I prefer to hope for a re-born eternity through the words and trust in Jesus Christ. We all have our own free choice of direction. I can only advise others to aim for that direction ... so I will not be looking to follow that suggestion of yours. Whilst we are on that subject, it would be as well to bear in mind that there is not likely to be any arguing or discussing our actions with our one and only almighty God creator after the point of death (which may come as suddenly as with say John Lennon), so it would seem sensible to aim to find the right way right now.... This I believe, is our golden opportunity of existence here on Earth.... Others may of course differ in their beliefs, but that is mine for the record, since you brought the subject up. I am not looking for a debate on this matter.

Instead of bring technical arguments and e.g. this useless 470 Ohm resistor you start to read from the bible and threaten me with sudden dead like lennon? Wow you are sick

@andyraffle ... If you are just wanting a basic timer, then here is one for you to try. It is working here fine on my board in front of me: http://everycircuit.com/circuit/5985557237989376

Funny, why cant you stay with this working version. You can also use a 555 which makes it much easier. A mosfet is not even part of the original circuit. You see “timer“ and ignores completely what the user already found and presented. Thats ignorant and respectless. @andyraffle has already a working circuit which needs only an explanation to tune its values. So what you saying is: this here is shit use my one which is better. Why cant you except this circuit. Because you do not understand this circuit. Do not make it to our problem, its your problem.

@hurz ... I offered a simple alternative design... as you did with your darlington pair. I also understand differential and integral working details of cap with resistors, which I suspect you are incapable of discussing mathematically. You are just a deluded know-all who started the spiritual discussion and then blamed me for doing so. The sudden death aspect is something which every single person has to live with, whether it be heart attack, accident or Lennon-like violence... the statement applies to all including me ... not just you. You are here again butting in with ranting aggression speaking out of turn and pointlessly.

My circuit is identical, its only tuned for minutes to handel. The type of transistors and the topology are identical. Yours is totaly different. Its even different in its interfaces! The only thing you took over is the 9V supply. So again, why dont you try to understand this circuit the author presented? You underestimate this community user as always. Its a working well known way to make timer. Dont suspect the worng things as you did too many times in the past. Aggression and zero knowledge is your part. Any news about the function of this 470 Ohm resistor, or are you still laughing about yourself LOL

BTW, you threaten me with violence like john lennon. Dont you think this is to much, and i better report that?

That 470 Ohm resistor was doing nothing but wasting current in the original presentation... putting it back in later when the OP understands the rc networking would be fine, along with necessary adjustments which would then be understood. My original suggestion presented a simple clear cap plus resistor starting point which I said would be a 'place to work forward from'. Why do you always launch in looking for the worst and spoiling everything?... here's why: ... You are frustrated about not being a qualified Electronics Engineer.... You are just a hobby enthusiast like most of us here on EC but have never come to terms with it.... so you put out as though you know everything instead of truthfully appreciating strengths and weaknesses in each individual, including yourself. Now fix it in yourself or shut up.... I for one am not spending more time trying to straighten you out.

You always talking about this “original presentation“ but this is just an invention you made. This post was never touched as i already said yesterday after your very first comment. You did that already in the past and it was a fake. This circuit here never changed while we talked till today. Why you fraudster need this story? Is your face red since yesterday? Ah, and you know i m a qualified electronic engineer, which you are obviously not. Why do you try to lift yourself if you are not even any engineer at all? Fraudster do that. The resistor is were it is and always was and you should sit down and try to understand what it is for. Meanwhile @andyraffle clarifies what reqirements he has for a timer. This is also an honework for you to think about what parameter are importante. Sandclock, Relay, BJT, mosfet, 555, arduino, buy it. This as a scale what can be used. Anyway, here we have a BJT and not a Mosfet which is for babys, even im pretty sure you will even fail for a professionell implementation with mosfets. You will trap if you try im 100% sure, cuz your knowledge in practical electronics is tooooooooo little. So fraudster forget the “original presentation“ which does not exist and try to understand the given real one by @andyraffle and dont tell him what he made wrong. He made everything correct so far, better you shut up.

You have said once or twice over the recent years that Computing is your bag ... not electronics. Now you are stating that you are an authentic qualified electronics engineer .... Lies and delusion seem to flow readily from you and no doubt you will not disclose your imaginary University and year when you gained this newly contradictory qualification.... I myself am just a hobbyist in electronics.(like you lol).

You are a hobby fraudster, while i have a degree in “Technische Informatik“ which is computer science and electronic in one degree. Cool he?

Ah.... 'Information Technology'.... I was a University lecturer many years ago, based in that department for quite a while. It is not the same as an 'Electronic Engineering' degree.... it simply covers basic electronics as a side issue.

Its 50:50, but if you know it better then me, im not surprised. Sounds like you were responsible for facilitymanagement. On one hand you laugh about users without degree on the other hand you do not even have any degree. So you laugh about yourself i hope.

I have a degree, though not in Electronic Engineering, just like you.... We are both hobbyists... That's fine... I don't care about degrees or proving superior knowledge in all things...Time you decided similarly.... life in fact is far more comfortable when not doing so. I realise that I know very little in life... you need to appreciate that in yourself and declare it....you would not be mocked by many for doing so.... and if any should mock, then they are the ones who still need to learn the necessary truth.

So what is your degree you dpnt care but used as not talk about this thread. “technische informatik“ wiki says https://en.m.wikipedia.org/wiki/Computer_engineering

I have divulged half of my life story already here in EC ... I don't really wish to follow that line more at this point.... enough to say that I know so very little. Electronics here on EC can be great fun if we can keep it light and helpful to each other. My little circuit is flashing away here in front of me and I tend to enjoy that level of simplicity. I made a different LED flashing circuit a few weeks back (a jason9 production). It was interesting and worked well on 4 AA batteries for a couple of weeks, but then it stayed lit instead of flashing ... due to a lowered voltage I suppose. My aim was to use as little quiescent current as possible in the hope of it lasting a month, so I did not set up extra voltage regulation... it used 2 transistors and one cap. I am now seeing how long a 555 will last....time will tell....such is my basic interest.

I had run out of vero board, so I soldered the components together directly for a laugh... it took some doing to ensure that the wires did not touch, but it worked fine. Then I hot-glued it with loads of blobs...You would have been proud of Mr Messy ... it was worthy of a major art exhibit in a gallery (Picasso eat your heart out). This is what I enjoy in electronics.

Thats great, but this is not “Put a wire across that pushbutton (that button should not be there). Get rid of the 470 Ohm resistor (it's wasting current).“

I don't know what your problem is.... andyraffle enquired as to why the original link circuit does not work in EC.... but he had copied it wrongly, whereby he had put a button instead of a switch and also put that in a different placing to the switch in the link. His EC circuit was thus not the link circuit. My suggestion was basically stripping everything out and starting afresh from a beginning point with only a cap and one resistor so that the concept of timing could be first viewed as an rc charging activity. Further additions could then have progressed from that first principle. His re-positioned button meant that an unnecessary amount of current was now circulating which he was presumably unaware of. Your initial input was an alternative approach of lowering that current and continuing with his (non- link-similar) circuit. I think that your approach could have confused him, since he did not seem to be aware that his button was in a different place to that of the link switch. Anyway... there were various approach methods to help, but your antaganism to my 'stripping to basics' suggestion was uncalled for and assumed that I was giving him a faulty completed alternative....You missed the part where I said 'work from there'... I hope this clarifies the matter and we can now put it to rest.

Why the hell a button or a switch makes a difference for you. It doesn't matter how you close or open a piece of wire. Original....... what is original if not this one here (check timestampes). So put a circuit together im curious how it look like. There was no other “original“ circuit were the switch was in a different “position“.

 A button and spst perform different functions... This OP was expecting the quick press button to perform the same as a spst and so enquired here as to why it was not working... Your answer of 'keep it held over' was your first approach. My first approach was to 'build the whole thing from scratch'. (with an intention of developing an understanding of what is needed for a quick press button to be implemented). Perhaps my phrase of 'that button should not be there' would have been better phrased as 'let's get rid of that button which is not currently working for you, whilst we re-structure'. (My Mosfet circuit link describes how such a basic button operates as a timer). This discussion is now going round in circles...I do not wish to continue with it.

Points not yet mentioned yet beyond the earlier discussion however: There is a necessary change of polarity in the original circuit cap in that setup, so a careful choice of cap is needed.... and a temporary voltage of approx -8v at the base needs consideration (b-e reverse bias max... datasheet?).

Now you start to tell me and OP what a button,switch,spst all is about? “the OP was expecting the quick press button to perform the same as a spst and so enquired .... WHAT ARE YOU TALKING. ARE YOU GOD? You are sooooo arrogant. You are splitting hairs spst or push button, and you are a mind reading godness. Is it you having halucinations, day dreams? Dont tell me such nonsense if you want taken serious. I see this circuit as it is, and there are no signs it was different. No the timestamp says, the circuit was unchanged. I dont care if spst or push button or a piece of wire you somehow close or open. I cant read OP mind, you can. You have big problems

Do you have any comment about reverse cap polarity and b-e reverse bias?

Yes, and you will be not happy about that topic. Why do you think you can read OP mind?

The cap dont care. Its negative voltage is only 0.7V you forgot to measure differentiell. Practical use of circuit is not your thing. Messing is

Arrogant again, “so a careful choice of cap is needed“

You are incapable of discussion without insult...I have finished talking with you...yet again.

The list of arrogant statements to this working circuit is getting longer and longer as you do not concentrate on its function. Just arrogance were no knowledge is behind

Why is this switch soooooooo importante relevant for you???????? http://everycircuit.com/circuit/5552356736630784

You are a master in RED HERRING

@andyraffle ... The switch/button relevance is here... but it's a change of design and an understanding of the function here which is more relevant...  In the default open-button position, the LED is lit due to nearly 1mA supply to the bjt base via the 22k resistor. When you then hold the button closed, the lower part of the 470 Ohm resistor drops instantly from its 9v down to zero volts and so does its attached cap terminal on the left. That 9v potential charge at the cap where you see the + on the left starts to discharge to that earth zero v. The -ve terminal on the cap was well below the 9v before the button press, and so that -ve cap terminal now drops instantly approx. that same amount to keep below the +ve side of the cap which is now at zero.... You can see that instant drop as - 8v on the scope if you highlight the wire between the -ve cap to bjt base. With the button held down, the cap becomes discharged where that right-side cap of -8v gradually heads towards zero ... the same zero now results on both sides of the cap.... fully discharged. That right side of the cap continues rising however (towards the voltage as expected at the 22k resistor...ie: +823mV). Note that the right side of the cap nearest the bjt became + when it crossed the zero point.... ie: the polarity changed.... you can watch the symbol change there. Notice also that throughout this time period during the holding down of the button, the bjt base voltage is less than the necessary approx 700mV which is required to activate the LED supply. As the now +ve right side of the cap continues to rise, it reaches that 700mV and the LED lights.(the button is still held down). That whole event with the button held down thus explains why the LED instantly went out and then re-lit. The time duration for that, depends on the cap value and the resistors which form the relevant rc network. A better design would be one where a quick press does the necessary tasks in a different way rather than having to hold the button down ... see my Mosfet link earlier here as an example. On releasing the button, the 9v is instantly placed at the left -ve side of the cap, which instantly makes that now +  on the left side ... see the cap symbol change. The cap right side retains the charged cap difference and is held at the 823mV keeping the LED lit.

You are on the way to understand this circuit, even late but better late then never. However, nobody does understand your.RedHerring about spst or push button or what ever. This is irrelevant for the function of this circuit. Even more interessting your first alteration does change the idle and active behaviour. So keep at least what we know from OP as relevant. In Vce it defines like this. Idle 0V Vce. Timer running Vce=supply. Timer event finish Vce=0V. While your first alteration is. Timer idle Vce=supply. Timer active Vce=supply. Timer event finish Vce=0V. But as you are a mind reading God, you already know what the OP is requesting. You ignore his circuit, but knows what he is thinking. You are just funny

Saw you delete your comment and made some corrections. Nice

So after all, we read the headline again, and we can say, after even @2cent agreed, this circuit is working fine! It took a while but the essence is out now. Have fun with unmessed electronics.

It only works with a long-held button press as it stood without alterations, which is not very practical, and probably the reason for the OP enquiring in the first place. Note again the good reason for him to consider the need for a non-polarised cap which I described, and note the time involved whilst the cap is in reverse bias between -7v and -8v which may not be within some datasheet max reverse b-e specs.

-8V is not reverse biased! Do not cpntinue telling bullshit.

Ahh, and use a switch instead a push button shouldnt be a problem to see for you there is no difference in circuit. Be a little more flexible in thinking you are like a grumpy cat.

As i said, you start to begin to understand this circuit. You are on the way. But noe you seems to turn around and and do not want to continue. It was such a nice situation to see you try to undetstand. But now everything is gone again of good spirite?

Nothing grumpy... just a natural discussion...A switch automatically holds down, a button is generally just meant for a jab to perform a task. An appreciation of the cap polarity mention would have been better than your first response about it.

Replace it with a switch, im sure you can do that. Dont worry you will make it. A little more assertiveness! You know were they are?

We cant take anything you say serious. Why and when is the cap voltage -7V? Remember, the world is making its stinky blinky circuits with electrolyt caps. Measure that again, and take your time

Stop insulting and just discuss, so that points can be clarified amicably... Highlight the base volts and get rid of all other highlights. Then keep the button held down. You will see that it drops to -8v as I described earlier, then steadily heads towards zero v. ... the time duration between that -8v and -7v is approx 0.5sec

Problem is you are not listening. Left side of cap if positive and right side is negative. This does !not! change in the moment when the SWITCH is closed. The cap does not have a REVERSE voltage. You must measure the voltage across the cap and not just one single point, as you so kindly explain. You might need as hobbiest this type of explanation. I dont. Stop insult me with your baby language.

The way I see it is this:... The base of the bjt is -8v below the zero v of the emitter. That to me suggests a reverse voltage between b-e ... ie the base flips from being +800mV above the emitter zero to being at a lower potential than the emitter ... explain.... is that not a reverse voltage at the b-e bjt junction?

Now you talk about the BJT. You are not even messing circuit you do also mess with text. Here you saying this: “Note again the good reason for him to consider the need for a non-polarised cap which I described, and note the time involved whilst the cap is in reverse bias between -7v and -8v which may not be within some datasheet“ later on you talk about vbe. If you know what you mean give as a notification. Take your time.

Can you please answer my last question.... was reverse bias involved at the b-e junction?

Use the right transistor and its not a problem, or lower the supply which will be difficult in your mosfet version, cuz 2-4V Vgs threshold and 5V suplly doesn't give a lot of precision and headroom. So it was a mistake on your side to talk about non polarised capacitor. You just mess with knowledge and text. Fine. Conclusion, we are lucky and the headline can be corrected, this circuit is working. Please verify any new statements you invent.

My descriptions for this setup are accurate, you are avoiding admitting that holding a button down for a lengthy period is a bad idea. Diverting to Mosfet circuit is irrelevant... standard Mosfet as described has that Vth of 2v to 4v fixed as per datasheet. It does not require altering, and neither does the more than adequate Vgs of my shown 9v... and it works fine on my breadboard. The headroom there is suitable (see datasheet Transconductance) and I don't wish to start a new sidetracking discussion here. ...time for you to admit that your 'hold the button down' suggestion was not a good idea.

You are always on sidetrack discussions, thats your way to make dicussions a pain. This button thing is irrelevant. Keep push it till your finger burns. It doesn't matter! You dont get that. Timer do have 100 different parameter, how they started, restart, resetted, rinning and interrupted and if the OP wish to have a push button, why not. In restart, on which edge or static. Edge with a given slope less then x ns... Its waste of time to have a discussion on this level. This button is just your methode to escape a real discussion. Thats what a red herring is. Last word to your toy circuit with a mosfet. Do it for 5V supply and the mosfets are having Vgsth of two to four volt!!! This is called tollerances and the manufactures do care only this range! Yes, range, if you want to make millions of your timer, you get Vgsth in a range and not FIXED. So you need an aligement in mass production which is already a no go and you need a poti which is also a no go for the costs. Vgsth is also temperatur depended. So your timer does run slower in hot environment. Funny toy you nade there. But to watch the principel its ok. Engineering looks different, but we do not expect that from a hobbiest. BTW IRF540N is a little to expensive and waste of material to power a 20mA LED. But what it makes a toy is charging a cap to 5V and going the discharge curve down and already switching at 4V or maybe 2V! Doesn't make it a good timer at all. Just a toy. 1V dynamic from alvailable 5V is ridiculous. Just a toy nothing else. If you are happy watching a toy, be happy. If you want real engineering, do it differnent.

Mosfets are only a toy in your imagination because you can not understand them very well, so you belittle them... The rest of the world uses them all the time. If the Vth happened to be 4v and the Vgs were to be set at 5v, then there would be 1v headway for activity. With the datasheet spec of 21A throughput per volt rise above the 4v Vth then our LED 20mA would have no problem at all arriving almost instantly at its needed current when switched on...... you just don't know such things. It is irrelevant anyway, because we have 9v, not 5v Vgs in my demo. This is all a usual ploy of yours to never admit getting something wrong... I have nothing more to say... so just have your usual last word and tell yourself that it makes you the winner.... and as for engineers.... a valid one would be familiar with e^x and its implications ... not like you, who was seen to newly discover it a day or two back on another thread. Let me know if you need help on basic electronic engineering theory and you can go on to discover how a simple LR network works. We will start with an introduction to integral calculus.

I repeat myself, your are a little nasty piece of shit and you know nothing about electronics, but you come here and tell @andraffle what he all did wrong, we cant take you serious you are a Messy.