Resistor for led

[ians]

A quick question :

Low voltage LED - 1.8 - 3.3 VDC

Power supply - 12 -13.8 VDC

If I want to install a single LED indictor for alarm status ... can I fit 1 x resistor at the 12VDC source and fit a bunch of those little LEDS located around the building ... or do I have to install a resistor at each LED

My concern is volt drop ... 12 VDC is already low voltage ... now installing a resistor at the source and then still running 20 meters of thin wire at a super low voltage that kind of distance ... just seems crazy.

I know I am being lazy ... but there are lots of smart people here ... maybe I am missing something ... maybe the power required for a single LED (1.8 - 3.3 VDC) is so low it wouldnt matter.

[Dylboy]

I don't know much about alarm stuff but could you perhaps do a restistor at each LED to get the required voltage. So keep 12V at source then parallel each LED with its resistor?

I am having a few early Friday beers in celebration of a great achievement so may not be thinking to clear either


Side note I feel I am on here too often when having a beer hahah.

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Edit, I now took notice of you saying shoudl I do a resistor at each LED so ignore all this...

[adrianh]

...more scary stuff....and I'm not even an electrician...

I mean come on guys ....parallel/series ...resistance | voltage drop etc....

[Justloadit]

The first question to ask, is what is the current rating of the LED?
Now that you know the current, you can calculate the resistor value for the specific LED, by using Ohms law.
R = Volts / Current Note the Volts value here will be Supply Voltage - LED Voltage. The Resistor value does not have to be exact, but can be to the next higher standard value.

You do not have to run the LED at its rated current, as this will reduce the LED lifespan, or it may be too bright for the application, especially when it is dark and you want to sleep, that damn things seems to light up the whole room.
My recommendation is that you place a resistor on each LED. Trying to place one resistor for all the LEDs in parallel will cause so many issues, and if something goes wrong, then all the LEDs will be damaged simultaneously. I ususally devide the rated current in half and go from there.

[ians]

I normally just put a resistor at each LED ... buy the LED complete with a wire to connect to 12 VDC ... however I am busy with a job and the technician has installed the resistor at the panel and run wires to directly to the led ... it seemed a bit strange.

Like the diodes on the relay outputs ... I can understand using a diode if the load is high ... but feeding another relay coil ... I am not a low current person so hence the queries.

Some strange things I see everyday ... another project ... there is a ratchet relay ... a siren and a resistor across the siren +/- output terminals ... so what happens when the alarm is activated ... the lights switch on but you cant switch the lights off until you re activate the siren ... which also creates a flashing light on the keypad ... indicating there is a problem with the alarm ... when you press and hold 7 it should siren trouble ... think what he did was just copy the old panel wiring.

This is one of the reason I am seriously considering going down the consultant route ... you call me I review the quotes submitted by contractors ... ensure that they have quoted correctly and not under quoted ... which generally results in some for mod short cut ... or site hopping to try keep the projects alive with limited funds.

I visit the site and check progress ... then verify the installation is complete ... so you dont get half new stuff and the other half left because it still works but the customer wouldn't know the difference.

Another big issue I find on a daily basis ... people not removing the old piping geysers wiring etc ... the roof space turns into the local dump ... you end up with all these cut ends which dont go anywhere ... which creates a fault finding nightmare.

[Dylboy]

Ians I personally would happily pay you for information on projects or jobs.. so if that helps then do the consultancy. Also if there is no hook on the line you can't catch a fish so throw the hook.


If inhad the bucks and no family I would pay you right now to teach me all you know and spend another bunch of years of "apprentice"

Feather in your cap.

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[ians]

Its a pity you live in JHB.

I was hoping my son was going to take over the business ... he worked with me for a while ...but it didnt work ... he works in a different field and is really good at what he does ... the attention to detail is what seperates him form the rest ... I have employed many youngsters ... but none who had an interesting the electrical industry .. they just needed a job to pay the bills ...

I had a person contact me ... he wanted his son to work with me to gain experience ... he was going to pay his son ... but it never materialised I tried that once before but when the youngster doesnt want to do it ... its a waste of time.

[ians]

When it comes to employing staff ... that say everyone is replaceable ... not true ... I had a guy work with me when I started this business ... he was an asset to this business ... we worked together for many years ... we had a disagreement over a vehicle ... I offered to sell him the vehicle and buy him a new company vehicle ... anyway cut a long story short ... he dropped off the vehicle ... I never saw him for about 8 years ... then he came back .. .but it just wasnt the same ... he eventually left again ... after he left the first time I sort of lost interest in growing the business ... I just continued on my own at my own pace ... I did try employ other more skilled staff ... got conned with a pile of false certificates ... since then been doing it on my own and just doing enough to pay the bills .. .then covid arrived ... had my best start to a year in 2020 ... lock down sucked the life out of me again ... here we sit just doing the daily routine to pay the bills ... talking shyte on the pub (forum)

[Dylboy]

I am hoping to head your way middle of next year, my sister is a private facility manger of sorts and they need some second verification done of someone verification. Basically 2 inspection and reports to then compare. But If if bears fruit or I can head that way and meet you would love it. Education is one thing and knowledge is another but learning from you would be inspirational.

I am young still in this industry, I am here now when light ballasts went from choks to drivers now to straight LEDs and all I cought was a quick glimpse of how it was before.




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[adrianh]

When it comes to employing staff ... that say everyone is replaceable ... not true ... I had a guy work with me when I started this business ... he was an asset to this business ... we worked together for many years ... we had a disagreement over a vehicle ... I offered to sell him the vehicle and buy him a new company vehicle ... anyway cut a long story short ... he dropped off the vehicle ... I never saw him for about 8 years ... then he came back .. .but it just wasnt the same ... he eventually left again ... after he left the first time I sort of lost interest in growing the business ... I just continued on my own at my own pace ... I did try employ other more skilled staff ... got conned with a pile of false certificates ... since then been doing it on my own and just doing enough to pay the bills .. .then covid arrived ... had my best start to a year in 2020 ... lock down sucked the life out of me again ... here we sit just doing the daily routine to pay the bills ... talking shyte on the pub (forum)

What has you giving up on your own business got to do with people not being replaceable - EVERYONE IS REPLACEABLE - Choosing not to replace them is a choice you made!

More often than not it is THE BOSS that should be replaced!

[Dylboy]

What has you giving up on your own business got to do with people not being replaceable - EVERYONE IS REPLACEABLE - Choosing not to replace them is a choice you made!

More often than not it is THE BOSS that should be replaced!

It is tough to replace that "one" yea everyone is replacable but they not all the same.


I proposed to my girlfriend to make her
My fiance in order to marry her.

Now that is a hard replacement so not everyone is replaceable.

Now yes that is life partner and not business but it is befuk difficult to get someone to care as much as you do... so I agree everyone is replaceable but no one places the same value as you do on your own business.

There are hidden gems of employees but not everyone hits lucky red 7 on the roulette table for the perfect or best employee

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[adrianh]

One has to be careful with mixed metaphors - Marrying your girlfriend would be (and should be) an emotional life long commitment. Such ideals have no place in business.

So, lets put the emotional / personal stuff aside and now focus purely on business.

There is a golden rule in business (and mostly in life too) - DO NOT GET MARRIED TO STUFF - be it ideas, products, a business, a car whatever...

Look, I got f*cked over by a boss, then I got f*cked over by a business partner and then I got f*cker over by an employee - I know what it feels like.

But...I have to quote PW Botha when he said "Adapt or die" - you see, we have to be able to adapt to changing circumstance - if the employee is useless then get rid of him, if the product fails then try something else, if the customer is an @$$hole then dump him and get another one....

You must learn to separate your own personal emotions and feeling and stuff from the business - the business is a machine that needs guidance and control like all machines - think of the business as an airplane and you are the pilot - you cannot let your ill feeling towards your co-pilot cause you to crash the plane because you are not paying attention. Of course a plane needs a pilot but a good pilot knows how to delegate - get the co-pilot to perform some tasks and get the autoplilot to perform other tasks...but... don't give up on flying the plane and letting it crash and burn because your favorite co-pilot decided to join another airline.

"The root of suffering is attachment"
~Gautama Buddha

Set you mind free - your business is "your airplane of money" it is not your wife!

[adrianh]

but no one places the same value as you do on your own business.

That is a given

There are hidden gems of employees but not everyone hits lucky red 7 on the roulette table for the perfect or best employee

No business should EVER be dependent on specific employees - That is the surest way for a business to commit suicide.

NOBODY EVER GOT STABBED IN THE BACK BY AN ENEMY - The people closest to you are the ones that f*ck you over - An employee is an employee - DO NOT ROMANTICIZE EMPLOYEES - They are cogs is the machine of business just as the boss, the lawyer, the bank, the supplier and the customer are cogs!

Now I am not saying that you should no value employees - of course you should value them - you should just do so using the correct frame of reference.

[Dylboy]

I agree with you. My dad got burnt by his business partner. I should heed those lessons as well as I saw what it did to our family.

Its a cruel hard world

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[adrianh]

Its a cruel hard world

Let me tell you a little story - I have two daughters, ages 21 and 23. They did lots of sport, life saving, gymnastics, played hockey, rode horses...lots more... and they both became provincial figure skaters. The one actually coaches horse riding for a living. When they were little they would fall off bicycles, inline skates, figure skates, horses etc. I drilled into them that THEY WILL FALL sooner or later and that they have to learn to fall "safely and protect themselves" - Saying that one should fall "safely" might seem strange but there is logic to it - If you fall off a horse you have to protect your neck, your back and your arms, if you fall during ice skating you have to protect your fingers etc. ....so they fell and got up...over and over again...My youngest daughter falls off the horses now and then and just shrugs it off as part of her life. She wears safety gear as much as she can to protect herself.....

So....to get to the point - you are going to get F*cked over.... things are going to go wrong.... customers will fail to pay etc....but...one learns to anticipate and prepare for such events....you kinda play "what if" all the time...I do it while I drive...What if that guy doesn't stop, what if the taxi comes up the wrong side of the road... what if the wheel falls off the car.... The thing is that you learn to protect yourself by being prepared and not relying on other people for your own well being - I check the road before I cross, I look in the mirror before I stop.... because there may just be some twat not paying attention.

When you look at the world through the eyes of "preparation and self reliance" you are NOT swayed by the ways of the world - you simply change gears and carry on - it is not a case of giving up, to the contrary, it is a case of being prepared....like a pilot practicing in a flight simulator...just in case the $h!t hits the fan - the preparation ensures that the pilot is not taken by surprise - he simply flies the plane according to his training.

Train yourself to embrace all aspects of life...we learn though hardship, failures and mistakes....Your enemies are your greatest asset for they force you to prepare and become wise to the ways of the world...

Another thing: The idea of "Falling Safely and protecting yourself" goes beyond the physical..."I said to them that they have to learn to protect their hearts"....people let you down, f*ck you over etc.. teenage girls kinda carry their hearts on the sleeve - One has to protect your heart and soul....don't let $h!t eat you up...One has to let things go...aka "sticks n stones"...Life is to short to waste energy on things you cannot change...