Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [electro-mechanical]

37 questions
29
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1 answer

How is it possible that HDDs are mechanically so robust?

Hard disk drives (HDDs) rely on a small read-write-head which hover about 70 nm over the platter 1, 2. The physical effect on which this hovering is based seems to be the ground effect 3, so it seems as if there is no electronic closed-loop control…
cakelover
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8
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2 answers

What kind of tactile switch is this?

I am trying to find some tactile switches similar (or even better, identical) to the ones shown. They are two stage, multi-way configuration. Depressing one click connects the common pin to pin 1, and depressing further (second click) connects the…
Mickrige McMahon
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4
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2 answers

Why do small dc motors have round shafts?

Small dc motors like the one below are commonly used for various tasks in toys and small appliances. These motors almost exclusively have perfectly cylindrical round shafts without any notches that have an almost polished appearance. The products…
Busti
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3
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2 answers

1980s AVTEL 4 colour mechanical display, how is the pixel state reset?

I stumbled on a retro Dutch video from 1983 where a large four color mechanical display is shown. Each pixel consists of a cube which can be turned in order to change the pixel color between 4 colors (white, green, red and blue), a carriage moves…
BuysDB
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3
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2 answers

Anyone got these optical encoders working?

I got these Optical Encoders from a local vendor and connected it to my arduino in the following order; (+)----> 5v (-)---> Gnd (01)--->2 (02)--->3 But, it burnt and smoked out as soon as I connected it. I am assuming it requires a current…
Samiul Hoque
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2
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1 answer

What is the proper name for a rotary relay?

Pre-1960, it was not rare for electronic devices to contain some kind of wheel or roller with circuit board traces on it. These traces would temporarily form connections between contacts as the wheel turned. The wheel could store a musical…
James Strieter
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2
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2 answers

Mechanical switch performance at high frequency (100MHz)

At high frequencies (>100MHz), "analogue multiplexer" branding gives way to "rf-switch" branding for switches which are controlled by logic levels. But if computer control is irrelevant mechanical switches require less engineer time and are possibly…
Edwin Shepherd
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2
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2 answers

Ebike battery sizing

I am building a homemade ebike using a treadmill motor. I know this motor is not the best for ebike application, but I am trying to work with what I have and see how far I can take it. I am wondering what battery capacity I need to maximize the…
MechEboss
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2
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1 answer

Overvoltage protection with a mechanical relay

12 VDC automotive environment, protecting the logic-level silicon. Instead of, say, the crowbar's thyristor, one could actuate a mechanical relay and cut no more than 10 A. Will that be enough to protect the circuitry downstream or is the bouncing /…
kellogs
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1 answer

PCIe card dimension half-length 106.68 mm × 175.26 mm specification deviation

As per Wikipedia and other sites, the dimensions of the half-length PCIe card are 106.68 mm × 175.26 mm. But as per the specification: Kindly clarify how the length of 175.26 mm has been arrived at for half-length PCIe cards.
Prashanth Kumar G N
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1
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2 answers

Can a DC motor safely exert torque opposite its direction of rotation?

I have a shaft that will turn in direction A. I want it to continue turning in direction A. I want a motor (preferably DC) to exert torque opposite direction A. Throughout most of its life, the motor will oppose whatever direction its shaft is…
James Strieter
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Linear actuator is not working with BTS7960

I am trying to run a linear actuator with a BTS7960 motor driver and an Arduino UNO. The code seems fine, wiring seems fine but after uploading the code, the linear actuator does not start. I am using two push buttons to extend and retract the…
Muskaan
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1 answer

PCB pancake slip ring brushes

I am designing a mechanical attitude indicator for the avionics simulator. I need a pancake slip ring, that drives servo (max 500mA at 5V) and some backlight. My idea is to use a gold-plated PCB and brushes mounted on the other PCB. But I am…
FeroFixxer
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Does it matter if power is applied only instantaneously?

If I build a railgun and apply say, 1 million watts, to the circuit to try to power a projectile forward through electromotive force, will it really matter if that 1 million watts of power is applied for just an instantaneous time say, 1 picosecond?…
Dorky
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Does a hybrid DC relay suffer from contact erosion (albeit much less than normal), or is it effectively eliminated?

Given a hybrid DC relay, I've been wondering if contact erosion is occurring (albeit at a slower rate), or if the design eliminates this entirely. (Assume that there is no snubber or other contact protection) I'm presuming that there is erosion for…
User Hostile
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