Activity for TonyStewart
| Type | On... | Excerpt | Status | Date |
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A: Why arc welding does not require high voltage to arc? - gas tubes, SCRs, and welder arcs all have negative incremental resistance. This means when conduction begins, the resistance drops like a crowbar and is sustained until the current drops below the holding current. - thus a typical ambient breakdown voltage for a sharp point of 1kV/mm is the sa... (more) |
— | over 1 year ago |
| Edit | Post #287969 |
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— | over 1 year ago |
| Comment | Post #288010 |
A good layout is one that meets or exceeds your expectations (or design specs). These specs form what is called Design for Manufacturability (DFM) for Testability (DFT) for cost (DFC) and for performance of accepting signal inputs by quick connection, signal conditioning for gain, bandwidth and CMRR... (more) |
— | over 1 year ago |
| Edit | Post #287969 |
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— | over 1 year ago |
| Edit | Post #287969 |
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— | over 1 year ago |
| Edit | Post #287969 |
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— | over 1 year ago |
| Edit | Post #287969 | Initial revision | — | over 1 year ago |
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A: What does it mean for a signal to have impedance? $$Z = R + jX $$ R is a real resistance that stores energy as heat and temperature rise which depends on the thermodynamic property of thermal resistance which is impacted by an enclosure to get hotter or cooler by forced airflow. Everything has some real resistance, even insulators with an elec... (more) |
— | over 1 year ago |
| Edit | Post #287952 | Initial revision | — | over 1 year ago |
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A: Testing instrumentation amplifier with differential signal It is important to realize that an ECG signal is high impedance and this easily picks up line voltage E-fields. Using a 50 Ohm sig.gen. is a poor simulation of the use of this circuit and also negates any common mode rejection using it as a single-ended amplifier with one input grounded. Ground by ... (more) |
— | over 1 year ago |
| Edit | Post #287524 |
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— | almost 2 years ago |
| Edit | Post #287524 | Initial revision | — | almost 2 years ago |
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A: What is the difference between rise/fall time and Turn-On/off Delay Time? To understand the timing, you must understand the cause. Delay is the time from input to output It is measured from +10% of input to 90% of output ( or a 10% change in output), unlike logic chips where the same voltage is used for input and output so delay is measured at Vdd/2 or 50% from input to... (more) |
— | almost 2 years ago |
| Edit | Post #287523 | Initial revision | — | almost 2 years ago |
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A: Minimizing Common Mode Radiation - Separating Grounds The problem with cable emissions from HS data and SMPS noise is very common even with UTP and ribbon cable with adjacent grounds on differential signals. I have seen this frequently on HDD testing at EMC sites, whereas the HDD emits nothing of interest. The problem is due to the imbalance of the... (more) |
— | almost 2 years ago |
| Comment | Post #286900 |
If I understand what you said refers to my description of a differential amp (DA) with 3 NPN's , " There is a negative feedback in this common-base (CB) stage driven by an input current " then I cannot agree.
The emitters are "common" to input and output so it is not a CB but rather differenti... (more) |
— | about 2 years ago |
| Comment | Post #287265 |
You would need a spectrum analyzer to determine the signal from line noise due to SMPS , motor starts and Triac dimmers in order to determine the Noise rejection required. But yes you should expect interference with the wider -40 and -60dB BW unless it was at least 6 to 8th order. (more) |
— | about 2 years ago |
| Comment | Post #287257 |
It seems you still use the single-ended topology but integrate current offset error with Hall, Rs or dual CT sensors to correct for the asymmetric current in each supply. (more) |
— | about 2 years ago |
| Edit | Post #287265 |
Post edited: more details |
— | about 2 years ago |
| Edit | Post #287265 |
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— | about 2 years ago |
| Edit | Post #287265 |
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— | about 2 years ago |
| Edit | Post #287265 | Initial revision | — | about 2 years ago |
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A: Ceramic filter vs ceramic resonator A resonator cannot replace a filter because the filter has multiple resonances to extend the bandwidth. For AM carrier modulation using a narrow band resonator with 0.5% tolerance of 6MHz or +/-30 kHz with a Q of 10k and its narrow -3dB BW can be as high as a crystal resonator but > 100 worse tol... (more) |
— | about 2 years ago |
| Comment | Post #286900 |
The simple ideas behind the differential amplifier are to ;
- eliminate the Vbe diode voltage offset from the input and choose any reference voltage for 0 output.
- use Ie to modulate gain when required
- choose either output for inverting or non-inverting gain or use both. (more) |
— | about 2 years ago |
| Comment | Post #287257 |
Does that mean you want it direct coupled but behave like a transformer AC coupled? Then the PFM or PWM drivers must have error feedback for the integral sum of current sensed from each to null the DC current and voltage feedback to null the error from the input voltage. So the answer lies in the ... (more) |
— | about 2 years ago |
| Edit | Post #287244 |
Post edited: so what |
— | about 2 years ago |
| Edit | Post #287244 |
Post edited: plot |
— | about 2 years ago |
| Edit | Post #287244 | Initial revision | — | about 2 years ago |
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A: Low-pass filter after the output DAC in CD players The oversampling is said to simplify the LPF yet the better reason is that it improves the SNR. Lower noise comes from better image rejection, lower filter ringing, and significantly lower group delay distortion in the audio band as the band edge is moved up. The majority of phase shift trav... (more) |
— | about 2 years ago |
| Comment | Post #285107 |
>Why does the collector current depend linearly on the base current?
When emitter resistance to supply rail is much greater than the base-emitter resistance re=26/Ie [mA] the voltage applied to the base is conducted to the base with Vbe drop. Thus there must be some relatively constant current g... (more) |
— | about 2 years ago |
| Edit | Post #287072 |
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— | about 2 years ago |
| Edit | Post #287072 |
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— | about 2 years ago |
| Edit | Post #287072 | Initial revision | — | about 2 years ago |
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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) |
— | about 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) |
— | about 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.
(more) |
— | about 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) |
— | about 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) |
— | about 2 years ago |
| Comment | Post #286900 |
The common terminal is not the least important, perhaps it is often ignored how important it is. (more) |
— | about 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) |
— | about 2 years ago |
| Edit | Post #287007 |
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— | about 2 years ago |
| Edit | Post #287007 | Initial revision | — | about 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) |
— | about 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) |
— | about 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) |
— | about 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 |