Activity for TonyStewart
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #287072 |
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— | over 2 years ago |
| Edit | Post #287072 | Initial revision | — | over 2 years ago |
| Answer | — |
A: pH Electrode Buffer - Offset when solution grounded DC offsets in hundreds of mV from different grounds may be coming from either the floating ground or the PE earth. The latter may be from rectified AC line filter noise shunted to PE. The former might be caused by front-end ESD protection diode rectification with DC bias and a CM signal large enough... (more) |
— | over 2 years ago |
| Comment | Post #287027 |
Conductance = S=siemens
(Volume) Conductivity, σ is "siemens per metre" (S/m) is the length/surface area
Resistivity (rho) = "ohm-metre" = area/ length (more) |
— | over 2 years ago |
| Comment | Post #286900 |
"Common" refers to input and output references that are shared. Vce and Vbe depend on the external resistors. While "e" is common to both.
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— | over 2 years ago |
| Comment | Post #286900 |
The differential BJT amplifier is well-defined in simpler terms.
Av=Rc/(re+Re)=Rc/(26/Ie+Re) (more) |
— | over 2 years ago |
| Comment | Post #285107 |
We know Ic is precisely controlled by the exponential function of Vbe and current gain is very inaccurate. This means every device has a wide range of Ic/Ib in the linear range and exceptionally wide variation in the nonlinear range down to 10% of the maximum current gain at Vce=Vce(sat) or usually r... (more) |
— | over 2 years ago |
| Comment | Post #286900 |
The common terminal is not the least important, perhaps it is often ignored how important it is. (more) |
— | over 2 years ago |
| Comment | Post #281971 |
I expect your measurements are accurate enough, but now you realize how reflections within 10 wavelengths or so can affect your results. (more) |
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| Edit | Post #287007 |
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| Edit | Post #287007 | Initial revision | — | over 2 years ago |
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A: Can confusing the plugs for earphones and microphones do any damage? If you mean electret microphone, no damage to JFET buffer. Microphone input won't damage a headset with it's current limited pullup resistor for electret Mics. (more) |
— | over 2 years ago |
| Comment | Post #286950 |
A bipolar switch rated for high Vceo seems to be all you need to protect the driver. Either high side PNP or low side NPN. >100V is easy to find. Your 1st plot is not to scale. (more) |
— | over 2 years ago |
| Comment | Post #286944 |
The ideal conditions are almost never achieved in ordinary ground communications, due to obstructions, reflections from buildings, and most importantly reflections from the ground out of phase. This fading can cancel up to all of the signal. So it is more important you define the path and all refle... (more) |
— | over 2 years ago |
| Comment | Post #286215 |
"across it" or it's own voltage is merely a value indicating the state of charge at some time. The actual charge Q = CV(t) for the capacitor's voltage. Your question is just about the semantics of a single test point (with an assumed common test point of 0V) or differential "across"
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— | over 2 years ago |
| Comment | Post #281971 |
What have you learnt? (more) |
— | over 2 years ago |
| Edit | Post #282053 |
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— | over 2 years ago |
| Comment | Post #286868 |
interesting analysis +1, close enuf for gov't work. (more) |
— | over 2 years ago |
| Edit | Post #282053 |
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— | over 2 years ago |
| Edit | Post #286867 |
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— | over 2 years ago |
| Edit | Post #286867 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Design high -pass filter with 2 points of the bode plot Filter design 101 - 1. given hypothetical high-pass (HPF) filter -3dB gain HPF at fc 2. attenuation of -8dB at fc/2 3. Assumptions gain = 0 dB at f>> fc 4. Ripple between -3dB and 0 dB is unknown but assume 0dB max for simpler case. 5. steepness of skirts << fc is unknown but we know 1s... (more) |
— | over 2 years ago |
| Edit | Post #282053 |
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— | over 2 years ago |
| Edit | Post #282053 |
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— | over 2 years ago |
| Comment | Post #282053 |
@#8176 The reality is your results of variations are real and certainly affected up to 10 or more wavelengths from reflections.
The other reality is s21 is also affected by these reflections with multipath, so the net effect is to measure RSSI where possible in your receiver and test the variation... (more) |
— | over 2 years ago |
| Comment | Post #286211 |
Anti-aliasing filters are always needed when the spectrum above the Nyquist rate fs/2 will degrade SNR with the resulting difference frequency output. Thus dynamic range and spectral values ought to be estimated with desired SNR.
Typically a sampling rate might be 3x the upper frequency is the sp... (more) |
— | over 2 years ago |
| Comment | Post #286215 |
**Is this interesting?**
All voltages are relative to some reference. The local ground is defined as zero volts, just like Protective Earth PE ground. So if one side of the cap. is 0V then the voltage drop is the same as "the voltage" (relative to 0V.)
**What is reactance, really?**
It is ... (more) |
— | over 2 years ago |
| Edit | Post #286866 |
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— | over 2 years ago |
| Edit | Post #286866 |
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— | over 2 years ago |
| Edit | Post #286866 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Circuit which create ac sine wave from dc pulsed signal This is about as simple an analog inverter that I can simulate, but warning, not for the beginner with resonance issues. The bridge diodes are 2f multipliers reduced to logic level with divide by 2 FF, then complementary inversion switches with a center tapped transformer with the tap having the i... (more) |
— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Comment | Post #286862 |
Thanks Olin, I added details to explain for others to understand why it is 180 + 180, with the assumption he knows there exists a frequency point at which -180 deg occurs from 3rd order (x90deg) phase shift) from 2L's and 1 C in a Pi filter. This is a slight change, from the Hartley. (more) |
— | over 2 years ago |
| Edit | Post #286862 |
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| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 |
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— | over 2 years ago |
| Edit | Post #286862 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Results of analysis of Hartley oscillator dont make sense This LC circuit depends on several criteria for stable linear oscillation; - 180 deg phase shift ( with 3rd order LC network) plus 180 degree inversion to achieve the oscillation criteria of 0 or 360 deg at gain >=1 Thus each reactance affects fo. - adequate bias current and impedance ratios with... (more) |
— | over 2 years ago |
| Comment | Post #286859 |
Not precisely, but you can filter the harmonic content of a broadband pulse to pass a narrow BW filter. Or you can phase modulate a square wave and filter any harmonic or fundamental.
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— | over 2 years ago |
| Edit | Post #286215 | Initial revision | — | almost 3 years ago |
| Answer | — |
A: What reactance actually is? Reactance is the lossless part of impedance that stores and releases energy E=1/2 LI^2 or 1/2CV^2 . Much like a spring stores energy when compressed or expanded. L is a conductor that stores current with charges flowing. Q=LI. C is an insulator with some dielectric constant , Dk, relative to a... (more) |
— | almost 3 years ago |
| Edit | Post #286211 |
Post edited: |
— | almost 3 years ago |
| Edit | Post #286211 | Initial revision | — | almost 3 years ago |
| Answer | — |
A: When do I need to put anti-aliasing filter in front of SAR ADC? Anti-Aliasing filter depends on the following parameters; 1. Signal BW 2. Sampling Rate 3. Sampling duration and thus BW of sample 4. LPF attenuation of alias spectrum above 1. From your SNR spec or dynamic range desired for resolution When sampling rates of 64x are used, ofte... (more) |
— | almost 3 years ago |
| Comment | Post #286209 |
Level shifting can be accomodated with >10k resistors to limit ESD diode current rating specified.
(more) |
— | almost 3 years ago |
| Comment | Post #286209 |
IF you want to detect tri-states, you need to specify the condition for the high-Zstate such as back driving with a 10k resistor 1/0 and detect that. (more) |
— | almost 3 years ago |