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Questions tagged [contact]

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1
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1answer
54 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 ...
3
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0answers
54 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 ...
0
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0answers
131 views

What is name this PCB mount AC contact?

I'm looking name this contact/connector or whatever called... This is using plug power strip... (it has facing white frame)
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3answers
82 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 ...
1
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0answers
48 views

Can I use a capacitor to reduce arcing on a 12volt DC switch?

My first motorbike had a capacitor across the points. I was told it was to reduce arcing on the points and prolong their life. I use 2 micro-switches and diodes to reverse the direction of the 12 ...
9
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4answers
281 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 ...
0
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1answer
170 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 ...
0
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3answers
80 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 ...
6
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3answers
860 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 ...
-4
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3answers
134 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
vote
1answer
145 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 ...
0
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2answers
122 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
59 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 ...
0
votes
1answer
92 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 ...
0
votes
3answers
126 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 ...
0
votes
2answers
864 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 ...
2
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2answers
406 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. ...
1
vote
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 ...
1
vote
1answer
1k 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'...
0
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4answers
3k 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 ...
-1
votes
1answer
51 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 ...
-1
votes
1answer
124 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 ...
8
votes
2answers
204 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
votes
1answer
565 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 ...
0
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4answers
794 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 ...
1
vote
1answer
861 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
votes
1answer
125 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 ...
0
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2answers
507 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 ...
0
votes
2answers
68 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 ...
0
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2answers
1k 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
votes
2answers
1k 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 ...
0
votes
1answer
1k 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
votes
1answer
835 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 ...
8
votes
4answers
7k 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 ...
1
vote
1answer
125 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 ...
1
vote
4answers
287 views

Low component count isolated contact closure without power on the remote side

Other answers here show a common way to allow a microcontroller to cause a contact closure (button press) within another device in an isolated fashion: use an optoisolator. I have the reverse problem....
0
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1answer
141 views

Weird problem when using relays

We have a product which is to do resistance measurement. The simplified schematic is as below. A 50mA DC current flows through the resistor, and we measure the voltage on the resistor's terminals. ...