All the switches I have have three outlets. I’m imagining my 5v is at the middle outlet, and then my circuit is on the left outlet. What should I do with the right outlet.
Should I consider a voltage regulating circuit?
Anything else I need to know about my idea? something I missed?
What does everyone else do who wants 5v on their breadboard? (soldered).
Hi Pix
Don’t believe this. You don’t know how a switch works??
That switch is a single pole double throw. (SPDT). The centre is common the 2 outer are each connected to the centre in turn depending on which way the switch is thrown.
There are variants of this. Some have a centre OFF position where no contact is made to either side. These are marked ON OFF ON.
Some of these are spring loaded so return to centre when released.
Some have another bank of 3 pins which are really 2 switches with the common lever . these are double (DPDT). Some even have 3.
The combinations are endless.
They used to be known as “C&K” switches (back in the day) because that was the only manufacturer.
Haha
Wait! Hear me out!
The number of times I thought I knew how something worked and then turned out to be embarrassingly wrong has caused me to be a little more cautious when phrasing questions. Trying to be humble and not assume anything.
I’m familiar with switches. I wasn’t worried about operation but I was checking thing like do I need to do any voltage regulation if I want a quality 5v?
I mean, for example, look at this thing below.
It seems way more complicated than I feel I need. But maybe those things are there for a reason? I dunno?
Hi Pix
Re your link.
Could be useful if you need 3.3V and 5V in the same project.
It “straddles” across a standard breadboard and puts 5V on the power rails and 3.3V on the other side. You must apply more than 6V at the input plug for the 5V regulator to work or USB 5V.
I think they work OK
Cheers Bob
Those power supply boards are very basic and no real protection. They use linear regulators which need to dissipate the voltage difference across them.
DC plug pack 12V, current drain 500mA (as the spec says). 3.5W across the regulator (7v x 0.5A), it will get hot and eventually fail. I have one that did that to me. You have a quality 5V 2A supply, use that. Do not use a phone charger, they have one purpose, charge a phone, they should not be used as a power supply.
You just need the switch in the 5V line to the USB-B connector you listed.
Just to throw in some relevant info, just watch out that most phone chargers have a power-saving feature where they will shut off if they aren’t drawing enough current. This current will vary but I usually find its in the 10ma - 20ma range, but could be much higher.
If you need voltage regulation it depends on what you are doing with your 5v.
When I need 5v I will use something like this:
And just use a 5v 2a wall adapter. It won’t do any PD negotiation though and has no resistors onboard so just use a basic wall adapter.
I’m not very happy with the quality of my soldering.
This was my first attempt working with enameled copper wire and I made a lot of mistakes along the way.
I broke my first USB connector so I had to de-solder and redo some work.
The patch jobs made it all a bit yuck to look at.
Next time I’ll know that you tinning the enameled wire helps bridge to connections.
Hopefully that will lead to a cleaner job soldering effort.
I also think I should have included a 0.1 micro-farad cap between 5v and Ground to even out any power fluctuations. I don’t think that would short anything.
However, it does work.
Thanks for everyone’s thoughts and assistance.
Pix
Hi Pix.
Yes enamelled copper wire can be a pain. Don’t know where you would use it outside coil winding. Most of this these days is “solderable enamel” which requires about 400ºC and try to be quick or you could oxidise the wire. The enamel can be removed by scraping (the usual method). or sometimes with Metho.
You think you have it tough, Think of the days before “solderable” enamel.
Then there is that little gem, “Litz” wire. Made up of quite a few thousands of strands of very fine enamelled wire. The strands individually coated. When terminated EACH and every strand had to be cleaned and when soldered EACH and every strand had to be properly soldered. A specialists job indeed. I would think this wire is still used in RF applications.
Cheers Bob
As simple as this project is to describe, you may find the DC rating of the switch to be a bit below-spec if you intend on drawing eg. >500mA from the USB port.
Hi @Michael.
Great thoughts.
Lucky, I did check this before starting.
The way I read these specs below is that I should be able to pull up to 3A.
Maybe that changes if I’m rocking lower voltages?
When opening a mechanical switch that is passing current there can be an arc.
With DC the arc can be more sustained, which heats and erodes the contacts.
Since AC crosses 0V 100x per second, the arc is ‘self quenching’. An arc may be present but the arc is only sustained by a voltage difference across the opening switch contacts. When the AC crosses 0V, there is no voltage to sustain an arc.
Even where there is no arc per se, the opening contacts essentially create a rising resistance while the switch is in the process of opening. That resistance creates heat which can erode the contacts.
Have you ever thrown a switch open and it felt kinda… sticky? For high currents that could be the contacts welding themselves together a tiny amount due to this heat.
Hi All
Just looked up Element 14 who usually publish data sheets.
Following is a screen shot of the ratings for C&K 7000 series switch which this one in question looks like.
This is what C&K say. And this is the data sheet that says it.
So if your switch happens to be a genuine C&K it looks like you are good for 5A DC depending on contact material. If it is some sort of clone of dubious origin I am afraid the jury might be out on this.
I don’t suppose you would be lucky enough to have any numbers on it or any other sort of identification.
Cheers Bob
Looks fine to me.
Most important thing is to make sure there is no possibility of anything shorting by moving a little.
This would be for high frequency transients, not really needed for this simple switch circuit.
Putting one on the breadboard would be a good idea depending on what circuit you are building.
