12 votes

What are the differences between linear and low-dropout (LDO) regulators?

The difference is due to the strongest force in the universe: Marketing. Both devices are linear regulators. This means they take a high and varying voltage in, and produce a low and steady ("...
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11 votes
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What is it about the cabin electrical supply on cruise ships that makes surge protectors dangerous?

From USCG Surge Protective Devices Onboard Vessels A marine casualty investigation of two separate stateroom fires onboard a U.S. Flag Container ship revealed that the sources of the fires were ...
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9 votes
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What causes the sound coming from electrical vehicles?

Correct, coil noise is generated in the windings of the motor because of Pulse Width Modulation (PWM) driving current. Different frequencies of modulation cause corresponding sound frequencies (may ...
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  • 7,444
9 votes
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What device is this, and how does it work?

Something like this? http://www.browninnovations.com/sound-dome/single-localizer-sound-dome As others have said, it is a speaker with a parabolic reflector to direct the sound down at the listener. ...
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  • 766
8 votes

What device is this, and how does it work?

With a description as vague as that, it was probably a parabolic reflector with a speaker at its focus. Pointed straight down, the "beam" of acoustic energy would be reflected from the floor right ...
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7 votes
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How can I find the emission power of a WiFi mobile phone antenna?

Not too sure if you will be able to find datasheet for specific cell phone. These are proprietary information and mobile phone manufactures usually don’t share this type of information in public for ...
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6 votes

When is DC power generation superior over AC power generation?

There are cases where DC power generation is superior to AC. If it's going to be transmitted by DC, and you can generate at the transmission voltage, or you can step up the voltage to transmission ...
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  • 3,681
6 votes
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Motor for a hydraulic pump in a hydraulic system

You are correct, getting oil pressure will require an electric motor as your source of rotation, potentially a gear box to slow that rotation down, and the pump itself. You'll also need a reservoir to ...
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  • 4,501
6 votes

What are the differences between linear and low-dropout (LDO) regulators?

At a very high level linear low-dropout regulators have a pass transistor, an operational amplifier, a resistor divider circuit feeding the operational amplifier and VREF. The operational amplifier is ...
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5 votes
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What is micro-electromechanical systems (MEMS)?

One way to think of MEMS is regular mechanical systems, but at a very small scale. Often these tiny systems are fabricated using technology developed for making silicon electronic chips, like ...
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5 votes

Does The W*nkBand Work?

Because this question has proven a little more derisive than I had anticipated (where's that engineering sense of fun/humour?)- I thought I'd attempt an answer as well, if only to prove it's an ...
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5 votes
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Hydraulic power source

Pretty much all electric motors demand a lot more power for starting from a dead stop than for generating motion in a steady state. There are a whole lot of schemes for smoothing out this 'inrush ...
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  • 4,501
5 votes

Why is minimum pressure specified on a PSU water cooling circuit?

You did not specify what materials you are working with and neither the dimensions. I made some assumptions. First of all, the coolant circuit is likely driven by a pump. Therefore you need to know ...
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5 votes
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What is meant by the terms "low pass sensor" and "band pass sensor" in a course syllabus?

You are combining two concepts. A sensor is any device that responds to a desired signal in some manner to produce an output that is used to detect the presence of the desired signal or to allow ...
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4 votes
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Why is minimum pressure specified on a PSU water cooling circuit?

The pressure requirement could also be to raise the temperature at which the water boils. The boiling point of water depends on the pressure it's at; higher pressure raises the boiling point, as the ...
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  • 2,989
4 votes

When is DC power generation superior over AC power generation?

When chemical/photovoltaic power generation is readily available, versus electromagnetic (based on mechanical power). If locally you have sources of mechanical power (wind turbines, steam turbines, ...
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  • 6,113
4 votes

12V outdoor lighting power consumption

A perfect ideal transformer converts some combination of Volts and Amps going into it, to some other combination of Volts and Amps coming out but a the same power. Put another ways (Volts in)(Amps in)...
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4 votes

12V outdoor lighting power consumption

The answer is #1, with a bit of an asterisk. If the bulb pulls 50 watts as it's rated, the current (power divided by voltage) will be 4.17 amps. We know that anywhere in a closed circuit, the current ...
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  • 4,501
4 votes
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Why is it bad to run power through BNC (RG58) cables?

Because it is not a power cable (Q1) using power connectors (Q2). BNC cable has a solid conductor and a ground braid to electrically shield and mechanically protect the conductor. Electrical reason: ...
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3 votes

Why are bird flight diverters shaped like a spiral?

Originally the spiral shaped devices were fitted to the earth wires on top of pylons as vibration dampers (the very top single wire on pylons is the earth wire). It was however noted that they also ...
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  • 66
3 votes

What is micro-electromechanical systems (MEMS)?

MEMS is a semiconductor based process that can create miniature structures in silicon. When these structures (sensors) are subjected to mechanical stresses (pressure, acceleration, yaw etc) they are ...
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3 votes

Generating practical power without an iron core, but with high RPM

the iron structure(s) inside a generator serve the purpose of minimizing flux leakage, which maximizes the utilization of the magnetic field in generating electricity. One of the ways in which they ...
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3 votes

What is the function of jumper pins on a 4 channel relay?

Each channel can be set to be triggered high or low. See User Manual
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3 votes

How to match a circuit relay online

For this specific relay, a quick search returns many results. One of them is from Mouser, an electronics component source. There is a link on the web site for the data sheet for the relay. Some of the ...
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3 votes
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Why design chargers with USB port on a side rather than top

I think that the power adapter was probably first designed for the North American market. For that market, the design is not flawed.
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  • 177
3 votes
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How to know which opto-coupler is suitable for high current application?

Optocouplers are made for milliamperes. You expect a switching circuit where a high current transistor or mosfet is controlled through an optocoupler or other isolation providing part. Such circuits ...
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2 votes

Motor Driver board: limited current

Make sure that the 12V supply is capable of sourcing sufficient current. This the source that powers the output A & B. The 5V input supply is most likely to power the logic circuitry. On PCB ...
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2 votes

How can I find the emission power of a WiFi mobile phone antenna?

Typically, the max is 100mW (20dBm). You can refer to an example wifi chip datasheet (This one is used in many mobile phones with Snapdragon processor) - https://developer.qualcomm.com/download/sd410/...
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2 votes
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Identifying affordable alternatives for low-frequency high-current DC-DC solid state relays

SSR or Solid State Relay is what you are after. You should be able to trigger this one right off the 3 volt rpi gpio. FOTEK SSR-40DA. Here is a DC one CPC1709J. Use a voltage divider or zener diode so ...
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2 votes
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Some questions about liquid nitrogen cooling

Regarding questions 2 and 3, I think you need to look deeper in the chemistry, reactivity, and heat transfer characteristics of Nitrogen. 1) It is not a noble gas. It is reactive, and you benefit ...
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