Russell McMahon
  • Member for 6 years, 11 months
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What is Radial and Thickness Mode Vibration in a Piezo Electric Ceramic Disc Transducer?
4 votes

Radial: Oscillatory waveform is between edge and centre. Thickness: Oscillation is across disc faces so will be higher frequency all else being equal. Axial and thickness are probably equivalent ...

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What is the purpose of the capacitors on LDO Regulator Circuit?
4 votes

The capacitors serve two distinct functions They serve as "reservoir" capacitors. If the regulator is somewhat remote from the energy source then sudden current peaks will cause $V_{in}$ to dip due ...

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Are there different solar panels for recapturing energy from household lighting?
4 votes

Some materials are somewhat better than others in lower light levels BUT in a typical indoor situation, even an extremely optimised material simply lacks the availability of input energy to convert. ...

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Why do these memory spaces start at F8000 instead of F0000?
Accepted answer
3 votes

Addresses are: A19 18 17 16 15 .... This expands on Dave Tweed's correct but brief comment: F8000 = 1111 1000 0000 0000 0000 <- A15 = 1 F0000 = 1111 0000 0000 0000 0000 <- A15 = 0 ...

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Is it possible that an electronic device "half-works" when the power adapter supplies too much voltage?
3 votes

Modern power adapters tend to be electronically regulated and not vary much in output voltage with load changes. Older ones that used iron core transformers were often less stable in output voltage ...

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Is there current multiplier circuit?
3 votes

My input is DC from a small DC motor which I use as a generator. My input current is 300 milliamps and I need 1200 milliamps as output. Is there some way to increase the output to 1200 milliamps ?...

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How can I connect mismatched solar panels in parallel?
3 votes

While it is possible to transform the output of either panel to match the other, the cost of doing so and the gains made are such that it is unlikely to be worthwhile. The characteristics of your MPPT ...

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How to identify low quality electronic components early?
3 votes

You do not say what sort of capacitors are involved. Tests will vary with capacitor type. Electrolytics can be tested for eg leakage, ESR, behaviour as they approach rated voltage, ... . Ceramic ...

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How can I determine the power generated by a regenerative braking system?
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3 votes

If I have an electric vehicle on an incline (m=17,3oo kg) I want to figure out how much energy it would generate by regenerative braking ... and maintain a set speed. Change in potential energy per ...

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Calculating time to heat up water at flow rate of 150 ℓ/min. @ 1100 bar
Accepted answer
3 votes

These two very simple to use formulas will probably allow easy order of magnitude scoping. Time to heat with given heating power T = V x 1000 cc/l x 4.17 x K / W seconds or T = 4170 V.K/W Power ...

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Why the word "mileage" is used for vehicles, instead of efficiency?
3 votes

Short: Fuel efficiency was long ago typically measured in miles traveled per gallon of fuel = miles per gallon = mpg = mileage. Nowadays we tend to use litres per 100 kilometre (BUT we don't say ...

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My customer wants to use my products to do something unsafe. What is my ethical obligation?
3 votes

An (almost) safe solution: With the information available from this question PLUS the highly relevant prior question Is it safe to treat a system downstream of a reverse-biased diode as de-energized? ...

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How to control suction strength on a breast pump?
3 votes

I don't know how this is done but the following sounds likely and easily achievable. It's how I would approach implementing a solution initially if I had no other information. Summary: IF you can ...

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How would adding a wind deflector in front of roof-mounted solar panels affect drag on an RV?
3 votes

Stress on panel mounts needs considering. This can be greatly reduced by a "ramp" that fully protects the panel from air impact in the forward direction. Flat plate drag for a panel will be <= ...

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Is it possible to make your own Q-Thruster?
3 votes

Yes, you could. But if it failed to work in the same manner that theirs reportedly did, you'd be in trouble, as NASA would not test it for you :-). If yours DID work then NASA may be interested. ...

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Could magnetic levitation transportation systems become a commonplace technology?
3 votes

Like many things, the driver is an economic one. Maglev is an entirely practical proposition but must compete in cost-benefit with other systems - notably wheeled ones. It generally fails to do so. ...

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Does a transformer use power when output isn't under load?
3 votes

A transformer offers resistance to AC current flow due to the magnetic field produced by the current flow. This "AC resistance" is termed "impedance" and is a function of number of turns, core ...

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What is the minimum current required to charge a smartphone battery?
2 votes

My input current is 300 milliamps and I am not sure if that will be enough to charge my phone's battery.* It will probably charge acceptably. This varies with product but in most cases modern ...

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Torque needed to draw back 220Lb's of weight?
2 votes

I have a crossbow with - 220lb (100 kg) draw pull. - 12" (0.3m) draw distance - 1/2" (12.5 mm) ball lead screw - 12 to 24v DC high torque motor - guided by two linear slides. I ...

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Wingspan formula for an Ornithopter
2 votes

Wing loading: The graph below provides areas for living and man made flying machines - and this can be seen to be a quite good log-log fit of mass and wing loading. See his text for comment on the ...

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Could a string of large offshore wind towers support a Hyperloop tube?
2 votes

Could a string of large offshore wind towers support a Hyperloop tube? It's a well defined [tm] engineering problem well within the physical capabilities of available materials and methods, so, yes, ...

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How to accurately calculate the rpm from a gear train
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2 votes

Obtain a cheap plastic hand crank generator or several and play. That will show you much of what you need to know. If you turn the handle 1/8th turn (45 degrees) in 1/4 second then its RPM is 60/...

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How to simulate car acceleration
2 votes

Real-world torque at standstill: This is not your main area of concern but needs addressing so that you can then properly deal with the main issue. Your statement at t=0 acceleration is ...

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How does a frequency to voltage converter work?
2 votes

As a general guide: One method is to provide a pulse of fixed width every time a slot passage occurs. The pulse widths are set such that at maximum pulse rate the output is either JUST 100% or ...

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Converting accelerating linear motion into constant rotational motion
Accepted answer
2 votes

Do you really mean ACCELERATING linear to CONSTANT rotary motion? A variable ratio drive as in the DAF cone drive now used in a number of Japanese gearboxes would work. Provided the accelerating ...

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Is battery-charge-stop-at-XX-percent circuitry not cheap?
2 votes

IBM/Lenovo ThinkPad line is basically the only manufacturer/brand of mobility devices that includes circuitry and software that allows one to vastly prolong battery life of laptops used as stationary ...

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Calculate energy (kW, or kJ) from Vapour Expander Generator
2 votes

Any engine that works at $50$ $^oC$ on the hot side is going to have a low efficiency. This may not matter but needs to be noted. The theoretical max possible $\eta$ (efficiency) is that defined ...

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Vehicle emergency high-deceleration braking and steering system
Accepted answer
2 votes

I gave this idea some thought some years ago -= catalysed by the events depicted in the video linked at the end. What you are describing is essentially a rocket. The concept is obviously possible as ...

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Would a structurally sound pressure cooker be able to withstand an internal vacuum?
2 votes

It MAY work, but there are no guarantees as a shape that is designed to place the body in tension throughout inder pressure will exhibit stresses under vacuum which there is no needs to design for in ...

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What is the simplest spring system that could produce recoil absorption comparable to that exhibited by the AA-12 assault shotgun?
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2 votes

The simplest, and possibly only, spring only system that would work like that would be made of nonexisteum as the energy would still have to be dealt with, and the power level exceeds what is seen in ...

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