71

Digital signals are highly susceptible to the noise generated by rotating the plug. For audio, these noises (cracks) are rarely audible unless they last longer than 50us (simply because of the fact that we're unable to hear frequencies over 20kHz). So, the cracks becomes audible only when the surface of the connector has deteriorated enough that the period ...


60

To electroplate the fingers with gold they must all be joined together electrically. This is done with a "plating bar" trace outside the final board area, which is cut off afterwards. Usually the board edge will be chamfered for easier insertion in the socket. Since chamfering removes the lower part of the fingers they only have to be wide enough to carry ...


58

The French means 'do not use to break the current'. In other words, this connector is not to be used as a switch. Only pull them apart when the circuit is drawing no current. With a 50A rating, and used with DC, breaking the connector circuit is likely to cause an arc as the contacts separate for long enough to damage them.


53

The jargon for this type of connector is "switched jack". Not only is it common for barrel jacks to have switches, but also for some other types of jacks, like phone jacks of all types. When you insert the plug, the connection between pins 3 and 2 breaks. This is useful for cutting a battery out of the circuit when a DC adapter is plugged in. Imagine you ...


53

Hot plugging. You want the power supply to be connected before the datalines. Some chips may latch if a signal is supplied to the signal pins before power is applied. This means the chip will internally short out and may get destroyed when subsequently power is applied. In the old days you had to power off you computer before you could add a peripheral to ...


47

Most likely many reasons, at least the following. It was a requirement for the connector to support hot-plugging. The connectors you mentioned do not support hot-plugging. Using an existing connector also means it is possible for someone to plug in two incompatible devices together just because they use the same connector. The connector also needs to ...


45

There are ribbon cables with twisted wires: Every few cm, there is a flat section to allow attaching an IDC connector. Looking at two product drawings it appears to be pretty typical to have 50 mm of flat cable out of every 500 mm.


42

Just look up a fractional inch to mm conversion chart. Then break out the drill bits. 5/64 inch = 1.9844 mm 3/32 inch = 2.3813 mm 7/64 inch = 2.7781 mm a 5/64 bit will fit the 2.1mm barrel but not a 3/32 a 3/32 bit will fit the 2.5mm barrel but not a 7/64


38

Vernier calipers can be used to measure both the inside diameter (i.d.) and outside diameter (o.d.). This works if you have only the device (receptacle) or the supply (plug). (Photo courtesy technologystudent.com.)


37

The little piece of rubber you removed IS the connector. Elastomeric connectors look like a piece of rubber and are commonly called "zebra stripes" because the conductive carbon stripes in the rubber look like zebra stripes when viewed from the end. Image from Wikipedia:


34

Figure 1. An 8-pin DIN connector (IEC 60574-18). Figure 2. Dimensions. Source: Amphenol. Figure 3. The female version has slots to accomodate the simple flat forked contacts visible in the three left sockets.


33

Compatibility with existing connectors is an anti-feature Let's imagine they used the then-common DB-9 DE-9 for USB. What would happen? Lots of mice used a DE-9, and it's used in a lot of other serial ports. People would be plugging a serial mouse into the USB port, and become frustrated when it didn't work. Availability of USB connectors is a problem ...


30

This must be British. For them "fit" means something like what we would call "install". For us, "fit" means how well something fits, meaning how good it is at mechanically going into the right mounting holes or whatever, or how effective it is overall in the role it is being used in. In this case "no-fit" means "do not install". This is often done when a ...


28

TP is the designator for Test Point. The plastic part just moves the loop part off the board, but you can see some without the plastic part. Nothing more than a small looped section of conductive wire. They can function as jumpers at the same time. They are used for test clips to grab onto. Some other options are 2 dimensional holes:


27

They are test points, as shown here. They are suitable for mini-grabber connections to lab equipment or probing


25

"For disconnect use only" should read "For disconnected use only" in the sense of "Only 'use' this socket (i.e., 'put a plug in or out of this socket') when the the power is off." A good translation would perhaps be "Do not use this plug as a switch" or "Do not use unplugging as a means to turn off." ...


24

Those are called Bootlace Ferrules and, yes, they're pretty standard in electrical wiring. They come in many different sizes, and each size has its own colour. There are also Twin Entry options, that allow two wires to be joined:


24

Solder a pin header Typically you solder pin headers to these boards. Either male or female. With male pins, you can solder them with the pins pointing down, so you can put them in solderless breadboards.1 1. This may ruin the breadboard strips


23

Other common terms used are "no placement" (NP) or "do not place" (DNP) but "no fit" would fall into the same category. It means the circuit board (PCB) has pads where a connector may be placed, but when you receive the board it won't have a connector installed. It will be up to you to source the connector and install it youself if you require it.


23

The mating half of that connector is designed so that the loops can clip into place and thus you have a connector pair that is more resilient to vibration and general movement i.e. the two halves are held together this way without relying on electrical contact pressure.


22

It's a kind of datecode. The mold for the plug actually has a small part that can be rotated with a screwdriver, to point the arrow at different numbers around the perimeter of the circle. They do this to either indicate a new month of manufacture, or perhaps a revision number. Note the 1 and the 3 on either side of the arrow. In this case, it's a datecode ...


22

Cables FL1000B20-WHT and FL1000B20-BLU are twisted pair with additional shield. Look at these symbols:


20

Those are barrel power connectors. Looking at Digikey, it looks like common inner diameters with a 5.5mm outer diameter are 2mm, 2.1mm, and 2.5mm, but that doesn't mean that your target application doesn't have a custom size which doesn't match any of these. The one I usually use for my projects is 2.1mm*5.5mm if I can, but as far as I know this is by no ...


20

AFAIK, it's not the fault of the cartridges themselves. The original NES-001 had a zero-insertion-force scheme which traded off ease of insertion for (what was later discovered) reduced effective life of the contacts. The lack of scrubbing action combined with everyone 'blowing' on the edges of the cartridges (plus lower tolerance for bent pins due to the ...


20

You have a few things to consider. Option 1 needs clearance behind it on the board to allow the locking tab to move. Option 2 suffers from a higher probability the locking tab will break off due to catching on something or pulling sideways on the cable. However it does give the pins a little protection when the board is being handled. You also need to ...


20

Google translate on your phone can do this: Parts prohibited area (部品搭軾禁止エリア) Pattern prohibited area (パターン禁止エリア) Soldering prohibited area (半田付け禁止エリア)


19

Disclaimer: I am clueless about EE, but read Japanese well enough to look this up. Black box: 部品搭載禁止エリア = "components/parts-loading prohibited area" (don't put stuff here, I assume). Diagonal lines: パターン禁止エリア = "Pattern prohibited area" (I don't know what "pattern" refers to in this context, but don't do it there). Diamond box: 半田付け禁止エリア = "solder-...


19

While one might expect that the socket's contacts would be a round metal receptacle, there is another design that looks like a fork. The two extensions of the fork make contact with the plug's pins by contacting the pin on either side. This fork-contact has a flat profile, and during manufacture, it is inserted into the slot that you see as a "line". The ...


18

Unless there is a figure like below, or some wording like "positive centre" then you can't tell. or: A supply can use positive or negative centre, as Olin says there is no standard. This is why you get the polarity switches on many of the universal DC supplies.


18

If you're using calipers, then use blue tack or something similar to make a mould of the internal dimensions of the plug or socket and measure the mold.


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