While waiting for components to arrive I have an other idea that may be bad or can work. Would be fun trying
I have a buzzer for lithium batteries. You connect the balance cable and set cut off voltage with a small button (between 2.7-3.8v). It makes a loud sound if any of the cells gets below your adjustment. It sends 3v to the horn that beeps.
If its possible, can I remove the horn and replace it with a relay that cuts off load when it "beeps"? A problem is that it beeps one time when you connect it to battery and that beep will trigger relay. I was thinking that maybe with a timer skip that first beep or something.
And that relay cuts off both load and buzzer itself. Buzzer consumes 9ma.
Is this something that can be done?
( This is not a replacements or anything I will choose instead of your circuits that I trust more. Just curious to know if it is working)
Like always, your answers are appreciated and exciting
Hy Rorut,
Yes, that can be done.
Can you give a complete circuit of the detector battery voltage detector.
My initial feeling is that the 555 circuit can be modified to stay in the fault state and the output of the 555 could be used to open the contacts of a relay. But it does depend upon the characteristics of the relay coil.
Nice of you to say you appreciate answers. In response, I like good questions.
spec
Hi Spec
Did not find any datasheet but here is a picture from the circuit.
View attachment 99561
I think I have a relay like this.
https://www.electrokit.com/rela-srd-1pol-vaxlande-5v.42004
Thank you very much
I think so. Thank you for verifying that the idea possibly worksThe relay should be OK. The 555 can drive 200mA and the relay coil is around 70mA.
This is how a possible solution looks at the moment off the top of my head. Connect the relay to the output of the 555 and modify the 555 circuit slightly. Would you be able to do that?
spec
No sweat Rorut,I think so. Thank you for verifying that the idea possibly works
Ah, I thought so.Thanks I will keep that in mind. Didn't find any more information about this and sorry if I was not clear enough.
Well, the bug really got me but frustrated I dont understand everything. So much to learn. Sad I didnt got the bug earlier
Thank you very much for such valueable information. I will definitely try and learn more in the order you describe. It is often difficult to know where to start. I think I need a good book to begin with. There is so many detailsAh, I thought so.
To get the basics of electronics is very easy. Electronics is heavily based on the application of maths so, to get started, you need arithmetic and fundamental algebra. All you need to do then is to visualize electrons flowing through a conductor (current), the thing that forces them to flow (voltage), and the thing trying to stop the electrons (resistance). It is very important to fully understand one stage and only then move on to the next stage. That way you are building on firm foundations.
The relationship between current, voltage, and resistance is defined quite simply by Ohms law: I=V/R
Then learn Kirchoff's first and second laws, which are also dead simple (obvious really) and you will have a firm grounding in the subject. I could not come to terms with Kirchoff's laws partly because of the frighting name but also because they are so simple. I thought I must have gone wrong because they seemed so obvious and basic- but no, that is what they are.
Next capacitors- conceptually awkward but not difficult
Inductors- as capacitors, but a bit more tricky.
Transformer- simple
The next move would be to learn the two fundamental functions of silicon diodes.
The next move would be to learn the two fundamental functions of bipolar junction transistors.
And then learn the one fundamental function of MOSFETs.
After that you have all the tools to design/understand some pretty sophisticated analog circuits.
The next move would be to learn the one basic function of an operational amplifier (comparators are pretty much the same)
And then you could design/understand some very sophisticated analog circuits.
The above would be the foundations of analog design.
Then there are the fundamentals of the digital field which, in principle, are not difficult either.
Things do get really heavy in advanced analog and digital designs though, but you needn't worry about that. As in most subjects, you never stop learning about electronics, and it is vital to learn by your mistakes- I do everyday.
If anyone is getting into electronics, or any field for that matter, getting a good book on the subject is essential.
It is all very nice for me to say all this after years of experience, and of course it is a gross oversimplification, but in principle, it is correct. I have tutored many people at work who have been struggling, even after learning the theory at university or tech college (by the way this is no indictment of academia- in fact most of the ex-grads were amazingly talented both in theory and practical). But after getting just a few basic practical principles under their belts, they have progressed well. I had the same experience when I was starting out in electronics; the advice came from other engineers, including grads, in our department. I seem to have a different way of learning to most people; I struggle learning the advanced stuff until I fully understand the basic function. Some other ETO members have said the same thing.
To take an example, many students knew how to do all the calculations for an opamp: gain, offset, frequency stability etc, but, in spite of learning all the difficult stuff, they didn't know how to apply an opamp (apart from in the classic configurations that is) in a practical circuit, because they didn't appreciate the one fundamental characteristic of an opamp: it cannot abide its two inputs being even minutely different and will do all it can, by altering its output, to achieve this balance. It does not matter where the opamp is in the circuit, this fundamental axiom applies.
As you may have guessed, learning about electronics is a hobby horse- it is the waste of talent for someone who is struggling that gets me.
Lecture over.
spec
Hi and thank you for your feedback DalDames. Yes NCR18650B. I think that is covered in the circuits made for me by the kind people here in the thread. I appreciate your inputHi everyone....if u have four Panasonic NCR3400 batteries, but I cant find that part number. Did you mean NCR18650B?Actyually the critical areas to get right in a cut off circuit (COC) is battery rebound, and this depends on the load (last) and the battery characteristics.Basically, without the correct window (hysteresis), the COC will oscillate: on load the battery voltage drops to 3.5V and the COC activates and removes the load. This causes the battery voltage to rise (rebound) and the COC reconnects the load and so the cycle continues.
The relay should be OK. The 555 can drive 200mA and the relay coil is around 70mA.
This is how a possible solution looks at the moment off the top of my head. Connect the relay to the output of the 555 and modify the 555 circuit slightly. Would you be able to do that?
spec
I show four lithium cells connected to a buzzer.Your 555 circuit is wrong and will not do anything. You should look at the circuits in the datasheet of the LM555 and LMC555.
You show four Lithium battery cells powering an LMC555. The four cells will produce 16.8V when fully charged but the datasheet for the LMC555 shows an absolute maximum supply of only 15V so maybe your LMC555 is destroyed.
Yes sorry, pin-8 and pin-1.My oscilloscope shows AC and DC much better than a meter that is very slow. I have a little battery powered amplifier with built-in speaker that plays an audio sound if there is audio AC.
An LM555 or LMC555 does not have a terminal called "Vin" but maybe you fed the buzzer output to the power supply input parts of your schematic shown as +5V?
led is just for testing circuit. Will not use it together with relay. Will do some more tests later. Thx audioguru!We do not know what the buzzer output is doing. AC? DC? Pulsing? How much output current?
The LMC555 is not powerful enough to turn on your 70 ohms relay coil plus the LED because its Cmos parts depend on a high supply voltage to produce high current. Also its output high current is less than its output low current.
The datasheet for the LMC555 shows its output voltage dropping a lot when its output high current is only 0.25mA with a 1.5V supply and dropping noticeably when its output high current is 2mA when its supply is 5V. Your 70 ohm relay coil draws 3V/70 ohms= 43mA.
The datasheet for the TLC555 shows even less output high current when its supply is only 3V.
The datasheet of the ICM7555 also shows very low output high current when its supply is only 3V.
Therefore the LMC555 cannot drive the relay plus the LED in your circuit.
An ordinary LM555 has a higher output high current but still not enough and its minimum supply is 4.5V.
Without the LMC555 does the buzzer output provide enough power to activate the relay?
I think the buzzer output can turn on a transistor or darlington transistor that can activate the relay and LED when they are powered from a higher supply voltage. The transistor have a delayed turn on.
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