Questions tagged [contact]

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38 views

Proper way of connecting wires to pins on polymer films

What is the proper way to connect wires to contacts from a thin semitransparent "plastic" foil (see images). There are slightly different types; the first one with the 4 pins in a row is the more ...
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1answer
48 views

NC Opening Contact detector to drive a NO relay Contact circuit

I'm looking for a simple +5.5vdc powered circuit (perhaps a PNP transistor driving a NO Reed Relay coil?) - I need a circuit that can detect when a pair of Normally Closed contacts with no voltage ...
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2answers
51 views

Sparking and electrical arcs in electrical contact

Consider a group of 5 batteries joined up to two pieces of finely engineered metal, that form common positive and negative bridging contactors for the group. If one of the batteries were to become ...
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0answers
51 views

How is the lever position read?

I am servicing a truck rig. This is the system that reads the "turn light switch" and "windscreen wiper switch". I would like to understand how the image plate 1 reads each position of the levers. On ...
1
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1answer
56 views

Why has the XBOX360 controllers battery pack an integrated breaker contact

Everyone owning a XBOX360 with wireless controllers came across a phenomenon where older controllers were switching off randomly while playing or if they were moved too quickly. Me and everyone i know ...
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2answers
123 views

Motor with two endstops using limit switches

I have a circuit where two limit-switches to be wired with motors to do the following functionality. It is to be used in a remotely placed device so that the intervention of microcontroller on the ...
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3answers
72 views

Contact Closure over distance

I have a contact (pushbutton) that's about 10 metres away of a Raspberry Pi. However; it behaves quite erratic and would trigger when for example an exhaust fan is started in proximity of the wire. I ...
3
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3answers
174 views

What is initial contact resistance in relays?

I am reading datasheet of a relay. I see a term, initial contact resistance in relays. What is the definition of this parameter? Thanks.
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2answers
97 views

In measuring relay contact resistance, should I use 4 wire measurement or calculate it using the voltage across the relay and current?

I'm reading mixed things online where a current from a typical ohmmeter is too low to accurately tell us the true resistance of the relay contacts. I've got a 30V 2.5A power supply, electronic load, ...
1
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1answer
38 views

Application based Heat sink design for Power diode

Instead of having a heatsink directly connected to the diode, I want to have a 2 mm layer of cold rolled steel in between case and heat sink(aluminium){for waterproofing as needed in the application}. ...
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0answers
55 views

Convert wet relay contact output to dry

I have a PCB which has output : GND and OUTPUT1. The contact is normally open, but when it closes it has voltage output of 4V and also closes the contact when checking on a multimeter. I want to ...
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1answer
31 views

Is a DMOS potential free? (in case of TPIC6C596)

I've been looking at the Datasheet of the TPIC6C596 and I'm not sure if the DMOS that is mentioned in the package can be used as a potential free. I also don't know in general if a DMOS can be used ...
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1answer
1k views

Modify Ring Contact Sensor in a series of wired security reed switches

After reading the instructables post on the simplisafe sensor I modified the ring sensor and tried to integrate it with my wired sensors. This is what I found: testing with a spooled wire about 20 ...
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0answers
98 views

Ensuring good contact between ring terminals and the screw terminals they're bolted to

I'm working on a high-current switching converter for research purposes. Because of the voltages and currents involved, many components use screw terminals to connect to wires. I haven't used screw ...
2
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0answers
144 views

How should one terminate litz wire?

When using Litz wire, the accepted method of stripping the wire is by dipping it in a solder bath, which effectively turns the end of it into solid-core wire, so my question is thus: How good is the ...
2
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1answer
115 views

How to contact aluminum busbar

For a project I need to handle large current, about 1200A. To do so I intend to distribute the power using busbar. Copper would be a good option but is fairly expensive and aluminum has almost the ...
1
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1answer
72 views

Schematic Feedback

I am looking for design feedback regarding the following schematic. The idea is very simple. The Controller board pulls the relay coil terminal low on the relay board to activate the relay.The relay ...
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0answers
155 views

Contact a very small area (impedance matched)

In my current project, I want to apply a voltage to a capacitor (top electrode on a thin film heterostructure) very rapidly. Since capacitors have their own charging rate \$(\tau = R \cdot t = R \cdot ...
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3answers
114 views

38999 contacts for pcb through-hole pass through connectors

So I'm working on a board that will act as a pass-through for a m/f pair of connectors interjecting to trace off some of the contacts to connect to another device for monitoring the signals. We did ...
9
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4answers
300 views

Contacts corroding - why?

These solder joints on the connector look strange to me (tarnished purple). In a more "advanced" state, they end up looking like this: In the last image you can see, it even "ate" the plating ...
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1answer
958 views

Difference between Rated Load & Max. Switching Voltage on Relay Contacts

Under the 'contact ratings' of a relay datasheet, there is a row for rated load, which specifies a 10A 30VDC load on both NO and NC contacts. There is another row which is the max. switching voltage ...
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3answers
103 views

Does the contact pad need to match the footprint shape of the SMD

If the contact pad is larger than the footprint, or has a different shape but is still large enough to make full contact with the SMD, will this lead to problems during reflow soldering? I am ...
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3answers
1k views

What is the purpose of the spring used in point-contact transistor?

Below on the left side of the illustration there is a point-contact transistor which is the first transistor invented in 1947: It seems the symbol of BJT actually comes from this point-contact ...
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3answers
211 views

Detecting human body current with raspberry pi [closed]

I want to be able to detect on my raspberry when a human contact is made with a GPIO pin (or a cable linked to a pin). I am pretty sure it's possible (for example when i see this kind of projects : ...
1
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1answer
418 views

Why use more than one contact in VLSI layout?

I saw the following layout in one of the standard cell library provided to us by the University. In the layout, the yellow color diffusion layer is connected to blue color horizontal M1 metal layer ...
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2answers
254 views

piezo stereo preamp

I have found several projects on piezo preamps but I cant find anything that can run 2 piezo inputs to make it stereo and uses potentiometer to control volume gain etc. What I found is "Collin’s Lab: ...
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2answers
82 views

Can you extend a tact switch with wiring?

This might sound like a wierd question but could I, in theory extend a tact switch by soldering wiring to the slots and putting the switch elsewhere. Basically I ride a motorcycle and have heated ...
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1answer
218 views

How to release wire from a Eaton Moeller M22-CK10 NO contact block?

I am attempting to rewire a fan to a M22-CK10 contact block. The device is shown below: My first thought was to push in the metal contacts above the red wire on the left. When that didn't work I ...
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3answers
321 views

How do I secure the connection to this battery (CR1616)?

I'm replacing the batter in a Game Boy Advance game cartridge. (Don't mind the bad solder job; the iron isn't handling well.) I've gotten it to work, but the battery is held down with very little ...
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2answers
2k views

Switch Current and Voltage Ratings

On a datasheet for a single pole, multiple contact switch, I see that there are a few contact ratings: non-switching (50VDC, 100mA), switching (5VDC, 100mA) and minimum (20mVDC, 1uA). What are these ...
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2answers
679 views

working principles of Electronic Throttle Body

Could someone shed some light on a working principle of this Electronic Throttle Body from MagnetiMarelli? (Found in BMW R1200GS motorcycle). Seems to be contactless feedback via the 4 tiny pins. ...
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2answers
1k views

My oscillator of 40Khz is not giving 40Khz signal at the output

I am putting a 40Khz crystal oscillator with 33Pf load capacitors. The problem I am facing is that as soon as I switch on the circuit, it is not giving me the pulse but as soon as i touch a metal or ...
2
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1answer
2k views

Limit switch on reversing motor

First- I've read through various posts about similar topics, looked at schematics, and I couldn't quite find something that matched this particular issue, here goes.. Cliff notes at the bottom... I'...
3
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2answers
2k views

Which surface finish for edge connector plating to increase number of mating cycles with sliding spring contact?

I'd wish to insert a small 12x33mm PCB into a USB slot multiple times a day. Because of that high number of expected mating cycles, the surface finish of the edge connector should be chosen wisely. ...
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4answers
4k views

typical value of contact resistance: 1) banana connector, 2) solder joint

Two separate questions: 1) What is the typical value of contact resistance in electrical connectors? I am interested mostly in a banana connector for delivering power supply from the source to the ...
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1answer
64 views

Relay data ambiguity

I found a relay with some characteristics written on it. The coil should be powered at 12VDC. The other data is unclear. IEC 255 3A 150VAC 5A 240VAC - AC1 5A 28VDC -DC1 So, in AC, the contacts should ...
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1answer
162 views

Does merging the chip and the contact pad in a chip-and-pin card make the whole module less reliable?

This picture is from here (A and B letters are irrelevant for this question). A chip-and-pin card like Visa Electron has a ...
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2answers
263 views

Wardrobe Under Shelf LED lighting that can be moved about freely

Hi I have seen a design for some LED strip lighting that is very simple to understand but am really looking for the various components so that I can replicate it. It seems that I don't know the right ...
6
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1answer
708 views

Why are contacts missing on some of these M.2 modules?

I want to replace a preinstalled Qualcomm Atheros WiFi/Bluetooth M.2 2230 card on my motherboard (ASUS Maximus VIII Impact) with another that has better driver support. This is what the card I want to ...
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4answers
1k views

Relay contact sticking while driving a capacitive load

I am using a Panasonic relay (ALQ105) rated for a resistive load of 10 amps 5A at 250V to drive LED bulbs. These LEDs have capacitive circuits in their ballasts and hence draw high inrush current when ...
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1answer
1k views

Calculating electrical contact surface area

First off, I am no electrical engineer: I am a mechanical engineer. I am making a saddle (holder for the rack) for contacting to a plating rack for anodizing. We are a small plating shop and I figured ...
3
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1answer
128 views

Help understanding a 30 year old schematic for a contact aligner

I got this old contact aligner I want to fix up but it is missing the control box, this is the diagram which is from like 30 years ago. Any suggestions on how to interpret this? J2 and J3 are the main ...
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2answers
711 views

Arc voltage on the relay's contacts when load is off

The contacts of the relay (not the coil of the relay) are connected in series with water boiler (2kW) and AC power socket (220V, 50Hz). Suddenly, relay stops its operation due to the electric arc ...
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2answers
74 views

Using modern electrolytic capacitor's can as a conductor?

I have a project cominig up where it would be benicical to have the large input decoupling cap's top surface be a touch contact point for Gnd for the circuit. I know that in the Old Days of yester ...
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2answers
3k views

How to determine a capacitor value across a switch carrying DC

The tiny rocker switches I'm using in a current project are supposedly good for 3A DC, which is at least 2X what I'd expect to draw worst case. It is supplied from a hefty Li-ION battery source ...
2
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2answers
2k views

Special USB Port With “Sensor” Contact

I've bought these special upright USB Type A ports with a "Sensor Contact" (the stray pin I've marked "Sensor Contact Pin"). I've been Googling on how they work, as well as sent about a half dozen ...
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1answer
2k views

Relay: how to calculate the maximum current and switching current

I need some advices on a design and not values in datasheet. I know that the carry current is the current that can be supplied continuously to contacts without exceeding the maximum temperature when ...
2
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1answer
979 views

Calculating maximum power dissipation based on contact area between two metal conductors

I am trying to figure out how to properly calculate the minimum contact surface area based on the maximum required power dissipation. Let me explain.. I am creating a custom semi-circular metal tab ...
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4answers
9k views

Is it safe to clean contacts with an eraser?

Today, while I was cleaning a RAM module, I was thinking about this. An eraser is really a easy way to clean gold/copper contacts in such modules. And it is really tempting to do so. I did it a few ...
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1answer
188 views

Relay Contact protection of inductive load and maintain electrical isolation

I've been reading Henry Ott's Electromagnetic Compatibility Engineering and one of the chapters is about contact protection. Looking at the various protection mechanisms to prevent or minimize arcing ...