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How do you know if a switch is a working one or not?

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Flyback

Well-Known Member
Hello,

I have just ordered 100 of the following switch: Part number = SDC-1-014

Switch (SDC-1-014)
http://uk.farnell.com/erg-components/sdc-1-014/switch-dil-dt-1way/dp/422680?ref=lookahead

...I am using this to switch 10mA in a 24V circuit. The switchs basically don't work..none of them. When one moves the slider strongly along...then the switch is in a kind of half connected state, and I can hear the relay coil that's being switched clicking away as it repeatedly switches....there is a series led, and I can see that flickering as the contact is not made properly.......after switching it, then in order to get a good contact, one has to 'tinker' with the slider until the contact becomes permanent....fiddling with it, gently nudging it until a good, continuous contact occurs

How could I have known that these switches were going to be like this (i.e. 'rubbish'?)

I wish to order a different switch to replace it. -one that works

How can I tell if the following switch is going to work or not?....
http://uk.farnell.com/jsp/search/productdetail.jsp?sku=1201430
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
That switch i highly unusual. It basically has a NO and a NC contact. It is NOT SPST unless you wire two terminals together.

Use your ohmmeter and connect on the wide edge In one position, the contacts along that edge will be closed and on the opposite edge the contacts should be open.

They are not common like an SPDT switch. It can be wired so the switch acts as an SPDT switch.
 

alec_t

Well-Known Member
Most Helpful Member
Type 1 looks expensive for a simple DIP switch :(. Have you tried passing, say, 0.5A or so through it? Perhaps there's a thin film of something on the contacts which could burn off or rub off with repeated use.
Type 2 is rated at only 12V, so not recommended.
 

Flyback

Well-Known Member
I know the 2nd one is only 12V, but it will only have 10mA instead of 100mA, so will this not be ok?
 

alec_t

Well-Known Member
Most Helpful Member
You'd have to ask the manufacturer. For one-off hobby use I'd personally take a chance, particularly if the switched load were purely resistive; but for commercial use, or use in large quantities, I would get a switch with the right spec.
 

audioguru

Well-Known Member
Most Helpful Member
The first switch is supposed to have gold plated contacts which are excellent for switching low currents. Maybe your switches were tested or used with high currents that burns away the very thin gold plating. Maybe the switches are defective (the gold is missing or has been burned away) or are fakes.

The second switch seems to be very cheap (cheep, cluck cluck?) because only one contact "might" have gold plating (if you ordered it with gold) and the other contact has silver plating that does not work with low currents (when it corrodes it does not make good contact at a low current, a high current or spark burns away the corrosion then it works fine).

Try switching a microphone (that has a very low current) with a switch or relay that has silver contacts. Crackle, crackle, crackle if any sound is produced.

I have never had a problem with a name-brand switch or relay that switches an extremely low current and has gold plated contacts.
 

tvtech

Well-Known Member
Most Helpful Member
Hello,

I have just ordered 100 of the following switch: Part number = SDC-1-014

Switch (SDC-1-014)
http://uk.farnell.com/erg-components/sdc-1-014/switch-dil-dt-1way/dp/422680?ref=lookahead

...I am using this to switch 10mA in a 24V circuit. The switchs basically don't work..none of them. When one moves the slider strongly along...then the switch is in a kind of half connected state, and I can hear the relay coil that's being switched clicking away as it repeatedly switches....there is a series led, and I can see that flickering as the contact is not made properly.......after switching it, then in order to get a good contact, one has to 'tinker' with the slider until the contact becomes permanent....fiddling with it, gently nudging it until a good, continuous contact occurs

How could I have known that these switches were going to be like this (i.e. 'rubbish'?)

I wish to order a different switch to replace it. -one that works

How can I tell if the following switch is going to work or not?....
http://uk.farnell.com/jsp/search/productdetail.jsp?sku=1201430
Flyback from Isoteria fame you have other problems.

I have bought hundreds of new Cheap Chinese switches in the past and....and not ONE has ever been faulty. No matter how low or how high within specification the switch is used.

You are hunting in the wrong area because you don't know what you are doing.

And don't understand how to describe the problem accurately.........

Lets say, you buy 100 new switches. Put the first one in and things don't work properly.
So, take the next new switch...same result....keep trying until you have gone through all 100 with the same failed result.

I suggest you stop now.

There is something else wrong and you cannot accurately describe it.

Or just put a 10uF to a 100uF cap across the Relay coil so it can latch maybe. Hopefully, your back EMF Diode is already in place across the coil too.

Regards,
tvtech
 
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Flyback

Well-Known Member
The switch doesn't need to be put into the circuit for the problem to show......with just the switch in your hand and probing it when the contacts should be closed, they are intermittently closing and opening.
I have put them into the circuit, because we'll just have to put up with it, and "twiddle" the switchs when we need to switch them......twiddle them until we can tease the contacts to close.
 

tvtech

Well-Known Member
Most Helpful Member
The switch doesn't need to be put into the circuit for the problem to show......with just the switch in your hand and probing it when the contacts should be closed, they are intermittently closing and opening.
I have put them into the circuit, because we'll just have to put up with it, and "twiddle" the switchs when we need to switch them......twiddle them until we can tease the contacts to close.
Big Warning :mad:

You are asking for problems....Whats this " I have put them into the circuit, because we'll just have to put up with it, and "twiddle" the switchs when we need to switch them......twiddle them until we can tease the contacts to close".

You are about to get burnt. Don't say I did not warn you.

The circuit IS NOT WORKING PROPERLY. Morons like you deserve all coming to you. Because you WILL NOT LISTEN.

And don't ask for advise here when all goes pear shaped. I am simply not interested. Go away.

tvtech
 
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audioguru

Well-Known Member
Most Helpful Member
I can go to an old RadioShack store and buy one of their expensive cheap no-name-brand Chinese switches. They have silver contacts that corroded into black insulation a few years ago so they do not conduct a low current anymore.

If I use the cheap switch at 120VAC with a few Amps then the cheap switch works fine like it was designed to do (but it might catch on fire since it is not certified to be safe).
 

tvtech

Well-Known Member
Most Helpful Member
I can go to an old RadioShack store and buy one of their expensive cheap no-name-brand Chinese switches. They have silver contacts that corroded into black insulation a few years ago so they do not conduct a low current anymore.

If I use the cheap switch at 120VAC with a few Amps then the cheap switch works fine like it was designed to do (but it might catch on fire since it is not certified to be safe).
Hi AG

You missed the point.

Switches are not Flybacks problem. He does not understand what he is doing....Dangerous to all involved with anything he is busy with..

I think tears will be the next thing....

Regards,
tvtech
 

panic mode

Well-Known Member
I have just ordered 100 of the following switch: Part number = SDC-1-014
How could I have known that these switches were going to be like this (i.e. 'rubbish'?).
How can I tell if the following switch is going to work or not?....
maybe they are rubbish but reading datasheets and ordering samples before paying for 100s of them can help avoid a lot of frustration. For example this one is not meant to be operated more than few times as serious wear results from merely sliding the switch (it is right in the linked datasheet). Like all DIP switches this one is not meant to interrupt current to load, the purpose of this switch is to configure some programmable device (also in datasheet). In other words switch should be in ON or OFF position before circuit is powered up. Basically you did get a wimp of a switch and I am not so sure that 10mA is really what your 24V circuit experiences. Can you post the schematic?

@tvtech
this forum has ONE purpose - gain experience by asking questions. and this is exactly what OP did - ask a question. please refrain from being rude, shouting and calling people names or telling someone to go away. there is no need for that, this is a public forum and anyone following guidelines is welcome. be an example, don't let frustration take over. thank you.
 
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tvtech

Well-Known Member
Most Helpful Member
[QUOTE

@tvtech
this forum has ONE purpose - gain experience by asking questions. and this is exactly what OP did - ask a question. please refrain from being rude, shouting and calling people names or telling someone to go away. there is no need for that, this is a public forum and anyone following guidelines is welcome. be an example, don't let frustration take over. thank you.[/QUOTE]

No problem panic.

If someone is about to do something something stupid...I will warn them :(

You tired of me ?? If so give me Neg Rep and I will understand and bugger off. Up to You. Easy stuff.

On the other hand, I plan on staying here. I don't ever recall having an argument with you Panic.
So what is your beef with me...

Why this outburst from you now...something worrying you :confused:

tvtech
 
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audioguru

Well-Known Member
Most Helpful Member
Why not use a toggle switch that goes click-click instead of a slide switch that goes scratch-scratch?
 

panic mode

Well-Known Member
@tvtech
i was not attacking you, it was (politely) mentioning that your post was inappropriate (i meant post #9). i expect more from someone who has been around for long time. there is no need for being rude, that's all. i never said i'm tired of you nor that you should not be around. all i said is try to be polite. is that much to ask? can you objectively read your post and say there is nothing wrong with it? in fact i have no idea where you getting with it. you shouted about world coming to an end because of circuit flyback is working on. until post #14 i have not seen any such circuit. is something bothering you? why are you so suddenly grumpy?

@flyback
do you have datasheet for your relay?
 

tvtech

Well-Known Member
Most Helpful Member
@tvtech
i was not attacking you, it was (politely) mentioning that your post was inappropriate (i meant post #9). i expect more from someone who has been around for long time. there is no need for being rude, that's all. i never said i'm tired of you nor that you should not be around. all i said is try to be polite. is that much to ask? can you objectively read your post and say there is nothing wrong with it? in fact i have no idea where you getting with it. you shouted about world coming to an end because of circuit flyback is working on. until post #14 i have not seen any such circuit. is something bothering you? why are you so suddenly grumpy?
Never mind panic

Yep, some stuff bothers me.

Especially those delving into stuff they know nothing about. Flyback comes to mind. Hence the warning.

My life of experimentation is over. Been burnt before.

So, trying to give guidance here. That's all.

tvtech

Regards,
tvtech
 

ronv

Well-Known Member
Most Helpful Member
For low voltage low current switches like you need usually gold over silver is used since there is no arc to break thru the silver oxides. But gold is usually very thin due to cost and not often found in slide switches where wear is also a problem. Who knows how long they have been sitting around and in what conditions. They are probably all oxidized and need higher voltage and current to break thru the oxide layer. If you must have a slide switch look for one with gold plating, but don't expect a million cycles from it.
 

panic mode

Well-Known Member
flyback,

PCN-112D3MHZ is a electromechanical relay with a 12V coil. your circuit will never turn it on. why are you using 12V relay in a 24V circuit? for that you should use PCN-124D3MHZ for example and no resistors.
 
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