Activity for Andy aka
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #285198 |
A zener barrier in the so-called "safe area" will still require 3 zeners if it feeds equipment that is contained in a Zone 0 environment. Ditto if the zeners are mounted in a Zone 1 or 2 area (UK/EU regulations are what I'm referring to because I think NA regulations don't always recognize a zone 0 s... (more) |
— | almost 3 years ago |
| Edit | Post #285173 |
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— | almost 3 years ago |
| Comment | Post #285201 |
All zener barriers must have a fuse to protect the zeners. If you don't need much output current maybe 100 mA will do but, it has to be a fuse that is line/phase voltage rated (i.e. 250 volts) and, it has to have high rupture current (4,000 amps from a long ago and fading memory) (more) |
— | almost 3 years ago |
| Comment | Post #285201 |
The fuse, in all zener barriers is never optional. The output resistors Olin shows suffice as current limiters. (more) |
— | almost 3 years ago |
| Edit | Post #285173 |
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— | almost 3 years ago |
| Edit | Post #285173 |
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— | almost 3 years ago |
| Edit | Post #285201 |
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— | almost 3 years ago |
| Edit | Post #285201 | Initial revision | — | almost 3 years ago |
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A: Flyback transformer with Intrinsic Safety > Please let me know if there is anything wrong with this logic. So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then these zeners, it's virtually a rubber stamp job. It's li... (more) |
— | almost 3 years ago |
| Edit | Post #285173 |
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— | almost 3 years ago |
| Edit | Post #285173 | Initial revision | — | almost 3 years ago |
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A: How long does it take for energy to propagate in a circuit? Try this out for size: - Image alt text Hope it's clear. Maybe a little simulation of 10 km 600 Ω line might help paint a better picture: - Image alt text The voltage (V1) that feeds the t-line via the 100 Ω lamp is a 1 volt step. The end of the t-line is shorted: - Image alt t... (more) |
— | almost 3 years ago |
| Comment | Post #284955 |
Energy does propagate. If it didn't propagate then how would we ever hope to see the light of our sun. It propagates entirely on it's own and then, when that light (EM wave) hits something that can make use of it, then, that energy is partially or completely used or reflected. (more) |
— | almost 3 years ago |
| Edit | Post #285138 | Initial revision | — | almost 3 years ago |
| Answer | — |
A: 208VAC triple-phase to single-phase conversion > I want to convert the power from the wall from 208V triple-phase to 208V single-phase before feeding that single-phase into the transformer I got. Try this using a 1:1, 208 volts isolation transformer: - Image alt text Or get an isolation transformer that directly delivers 230 V AC on... (more) |
— | almost 3 years ago |
| Comment | Post #285070 |
Why do you say convert triple phase to single phase when this is contradicted by only having two of the three hots available. Please fix this. It's a big deal. (more) |
— | almost 3 years ago |
| Comment | Post #279876 |
Show your interface circuit up to the first line of chips. (more) |
— | almost 3 years ago |
| Edit | Post #284863 | Initial revision | — | about 3 years ago |
| Answer | — |
A: Resistance of digital ampmeter Image alt text You might get lucky and be able to measure the input resistance using this method. It should work because the black socket (common) is shared by all measurements. (more) |
— | about 3 years ago |
| Comment | Post #282671 |
When it is critically damped, there is not oscillation. (more) |
— | about 3 years ago |
| Comment | Post #284514 |
There is no input shown and no output shown and, with the component values you have shown, the BJT might just as well be removed entirely. (more) |
— | about 3 years ago |
| Comment | Post #284282 |
Let's **not** start with assuming *that torque vs. rpm of the load is linear.* (for extremely good and sensible reasons). Your follow-up question makes no sense either. (more) |
— | about 3 years ago |
| Edit | Post #284234 | Initial revision | — | about 3 years ago |
| Answer | — |
A: Inductance vs frequency Inductance is defined by the shape of the coil, the area of the coil, the number of turns in the coil, the distance between turns, the ferromagnetic permeability of material within (and surrounding) the coil and induction to other not-so-obvious conducting parts. Frequency lowering (with a fixed A... (more) |
— | about 3 years ago |
| Comment | Post #284074 |
Do you mean C2? (more) |
— | about 3 years ago |
| Comment | Post #283960 |
Sorry but that's garbage. (more) |
— | about 3 years ago |
| Edit | Post #283993 |
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— | about 3 years ago |
| Edit | Post #283993 |
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— | about 3 years ago |
| Edit | Post #283993 |
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— | about 3 years ago |
| Edit | Post #283993 |
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— | about 3 years ago |
| Edit | Post #283993 |
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— | about 3 years ago |
| Edit | Post #283993 | Initial revision | — | about 3 years ago |
| Answer | — |
A: Coupling of inductors > Which will be the total inductance of this circuit? Quite simply, if both the individual 1 henry inductors are perfectly magnetically coupled then, the net inductance will be 4 henries. If both 1 henry inductors are totally uncoupled, then the net inductance is 2 henries. This can be... (more) |
— | about 3 years ago |
| Comment | Post #283960 |
*Now current entering one coil marked with a dot, produces a current exiting the couple coil at its dotting end.* - this is incorrect. Induction causes a voltage to be induced. Think about it - how can a current be generated by L2 in the opposite direction to that flowing in L1 when they are in serie... (more) |
— | about 3 years ago |
| Comment | Post #283430 |
A signal that cannot change is generally recognized as being 0 volts. (more) |
— | over 3 years ago |
| Edit | Post #283389 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Adding resistance to varactor circuit > in my schematic we must add R1 correct? Yes that works except: - Image alt text > One last question if we deliver voltage to a house are there varactors which can handle 120V AC No, they don't exist. (more) |
— | over 3 years ago |
| Comment | Post #282733 |
Where did you uncover the equation? What document did it come from? (more) |
— | over 3 years ago |
| Comment | Post #282738 |
Why should we be able to transmit power from an antenna billions of miles? What transports this power? You need to study EM field radiation. That's a far bigger issue than a wires apparently being an open-circuit. (more) |
— | over 3 years ago |
| Comment | Post #282746 |
If you leave your name, address and utility company reference, I'll contact them on your behalf and arrange for you to go on a low-tariff supply. (more) |
— | over 3 years ago |
| Edit | Post #282725 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Diodes used in mixers There are plenty of ways a single diode and a couple of resistors can perform multiplication (RF mixing). Consider this circuit that takes two inputs (a 1 MHz sinusoidal carrier wave and a 10 kHz triangle wave used to modulate the carrier): - Image alt text Now look at the signal on the cathode... (more) |
— | over 3 years ago |
| Edit | Post #282710 | Initial revision | — | over 3 years ago |
| Answer | — |
A: Extract DC component of mixed signal > How can we extract a DC signal from a mixed signal? You use a low-pass filter with a cut-off frequency that is significantly lower than your lowest AC signal frequency. If you need better filtering use a higher order low-pass filter. If you need both fast response to the DC level and high AC ... (more) |
— | over 3 years ago |
| Comment | Post #281971 |
EMI could do that. Maybe make an antenna that works in a close but quiet part of the spectrum and test? (more) |
— | over 3 years ago |
| Comment | Post #281967 |
Pick several and fit them all to cover as many variations as you think are required. Also fit inverting links so that a barrel jack with the centre pin with opposite polarity can be reversed. Or use a bridge rectifier to automatically produce the correct polarity.
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— | over 3 years ago |
| Comment | Post #281634 |
@2kind ESR is very important. If the ripple current is high such as in inductive chargers using resonance then the ESR can dissipate enough heat to burn a capacitor. Plenty of other applications require low ESR. (more) |
— | over 3 years ago |
| Edit | Post #281634 |
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— | over 3 years ago |
| Edit | Post #281634 |
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— | over 3 years ago |
| Edit | Post #281634 | Initial revision | — | over 3 years ago |