Hot answers tagged

38

This is KN-4A socket. Widely used in Eastern bloc countries in many types of electric equipment with a motor, mostly in sewing machines. What is important - this socket is not provided for powering up motor or a whole device directly from mains. To make a full circuit you need a steering pedal and special cord. Pedal and cord looks like this (note similar ...


31

If you are not going to swap / change / reprogram your ICs just solder them. I have never overheated any DIP IC during the soldering. It is not easy to overheat them. Maybe 40 years ago ICs were more sensitive but nowadays it is not the issue,


23

If you're in a design stage, a socket can turn a real pain in the neck into a momentary problem, allowing you to swap out that microcontroller with, say, a burned out DIO, with a brand new one, in seconds. Otherwise, break out the iron.


22

What you are waiting can be two things. One is for the ISP to "release" your dynamic IP address, and after 'x' minutes, when powered back on, the MRC (Modem/router combo) will be re-assigned an IP address to its MAC address. The other reason is to allow a internal capacitor to discharge completely to allow the volatile memory that contains the cache to be ...


20

If you are skilled in soldering, overheating the DIP package while soldering shouldn't be a problem. Also, the sockets can introduce problems themselves due to bad contact. Just keep the soldering short, below 3 seconds per pin as a rule of thumb. Sockets are great when you are working on a prototype and there is a real chance of blowing up the IC during ...


17

Breaking the chip due to overheating during soldering should be very rare. However, if you have the chip soldered down and end up breaking it during testing, it is very helpful to know this trick: Instead of trying to desolder all the pins of the broken IC, just cut them off with pliers and then clean up the holes with the iron.


11

Good answers here already... I'll add my two cents worth. ( Though I guess that's a nickel now we ditched the penny in Canada. ) When prototyping the first go around of a board and your confidence level is not that great in the design or PCB, sockets often make debug and rework a lot easier. With a socket, you have the ability to quickly "lift" a pin. ...


11

I've broken many more ICs trying to pry them from DIP sockets than from heat or ESD damage from soldering directly. Even using a chip extractor can be risky. That said, in the analog world DIP sockets have been useful for trying out different op-amps for audio applications. You can try one US$10 op-amp, stick in a US$0.50 one, realize they sound the same, ...


10

I suppose since the earth prong is also longer on these BS 546 plugs, if you could partially plug it in the wrong way (say earth to phase), then someone else touching the appliance at the same time could receive a shock. So the earth prong is thicker so that you cannot plug it in even a little bit in the phase/neutral holes. (Rotational asymmetry would ...


10

There's different way these things can fail, and in most, they might still be using power. I've seen all three: failure modes where the bulb "shut down" and used totally insignificant amount of powers, failed bulbs that used way less power, since they had no emitter to drive, and failed bulbs where the built-in supply was constantly trying to drive a ...


7

Some devices don't fully power down when you turn them off, they simply go into a low power standby state. By unplugging it you make sure that it shuts down complete and has to go through an entire reboot sequence. The 5 minutes are a combination of allowing the internal power supply to completely discharge and for the link to your ISP's equipment to drop. ...


7

Paul I'm going to go out on a limb here and try to answer this. In my experience, the 80's era and prior did use sockets quite often for everything from IC's to transistors. There may have been several good reasons for this: If the part failed, a socket simplified repair. Most IC's were DIP package (relatively low pin-count) so could be socketed easily. ...


7

That header is a Molex 2.50mm pitch SPOX wire to board header system. There are also several other manufacturers that make clones of these. Here is the Molex data sheet for the 4-pin shrouded PC mount header. http://www.mouser.com/ds/2/276/0099990988_PCB_HEADERS-137537.pdf This particular one has inline pins for through hole mount. There are also versions ...


7

High-current barrel connectors are tricky. Generally the current capacity is determined by contact area between two mating surfaces. More area means more current. Cheap barrel receptacle (jacks) have only one spring, like I marked in red here: A mating plug usually has a simple cylindrical geometry, with no springs or splits. When plugged in, the bottom ...


7

A switched outlet with nothing plugged into the outlet will generally not consume any power when the switch is turned on. There are a few cases where this may not be totally true. Some outlets may have an indicator to show that the outlet has a live power connection and the indicator circuit will consume a small amount of power. Some indicators would be a ...


6

Using socket packages have some cons and pros. Usually with the cost of integrated circuits rising, it is good general advice to maintain the chip for the next time use. But sockets, most often cheap ones, might find oxidation over time so your electrical connections may be lost. Also the PCB traces would be covered by the socket frame which prevent you from ...


6

In 10 years of working in the microcontroller world, I've never used a socket and never regretted it. The risk of having a bad contact in a socket is real. Old computers are notoriously unreliable because of sockets. On old computers, many times you have to push on every chip to reseat and "clean up" the contacts to the socket. I would not worry about ...


5

There are two ways to answer this. No. Voltage is a relative measurement, and in any AC power system (American or European), one voltage oscillates above and then below the voltage of the other. Thus, from the perspective of the appliance, which has connections only to the two prongs of the outlet, it's impossible to tell one from the other, because the ...


5

If you have a 'hard' on/off switch this should have the same effect as pulling the plug. But a lot of devices nowadays have a 'software managed' switch, which is of course useless when you want to force a hard reset on the software. The 5 minutes is to make sure that the device has really lost its power. A power supply unit, especially a switched mode one, ...


5

An important concern is that it must be impossible to insert the ground/earth pin into the live/phase/hot receptacle of the socket. One way to do this is to make the ground pin larger, so that it cannot fit. In North America, this is done by making the ground pin round, while the live/phase/hot is flat. It is also common to make the ground pin longer to ...


5

Yes, you have a problem. Basically, your "ground" is floating with respect to neutral. This suggests a failed connection, and this is potentially life-threatening.


5

The female connector includes a spring, which puts pressure on the contacts. The higher the pressure, the higher the current the connector can be rated for. The spring used in the females you've seen so far limits the current to 3A, even when mated with an ideal male connector. The male connector is simply a solid cylindrical contact which, when mated with ...


5

This is a really stupid thing to do. You are measuring the difference in voltage between the mains and the ground through your body's capacitance. You have not given a make and model of the multimeter or a link to its datasheet so it is not possible to construct an equivalent circuit. The problems are that you are using a meter for purposes other than ...


5

It's a fairly unique hole pattern, and the only connector I found at a cursory glance that matches is the Kycon KPJX-3S: It is a 48VDC-rated power jack, and the applications listed in the datasheet seem in-line with the comment you made about it being on a printer.


5

If the switch is set to the on position but nothing is connected to the socket, will any energy be used/wasted? simulate this circuit – Schematic created using CircuitLab For electrical energy to be consumed current must flow. Air is a very good insulator. We use air as an insulator on the high-voltage lines you see criss-crossing the country. When ...


4

Most alligator clips have a hole at the end opposite the grabber part, often used for soldering a wire onto. However you could use that to mount the alligator clips so they stick off one end of a PCB, like this:


4

The third terminal is like a switch. When you have nothing plugged in the third terminal is connected to one of the others. When you plug something in the third terminal is disconnected. It's primarily designed for automatically switching between battery and external power. The schematic symbol is: With nothing plugged in pin 2 is connected to pin 1. ...


4

I believe the true answer here is not only a technical one, but also the simple fact that people are idiots. Especially those who end up calling technical support for router issues. That's a sad fact but unfortunately it's the case. Support agents there get the kind of calls where people ask why their device does not work and end up being told that they need ...


4

I'm guessing that the earth connection is broken somewhere and those parts (MOVs or Capacitors) are leaking or conducting a bit of current to the 'earth' pin on the power bar sockets. One of them could also have failed short, but you would not see any difference with a voltmeter. In any case that current should be conducted out to the earth terminal on the ...


4

I think this is pretty close: http://www.digikey.com/product-detail/en/8-215079-0/A99470TR-ND/1955697


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