Activity for TonyStewartâ€
| Type | On... | Excerpt | Status | Date |
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A: Confusion in operation of analog computer The two-terminal symbol for the attenuator comes from 3 pin potentiometer (pot.) referenced to 0V = "GND" Image alt text The summing amplifier is always inverting and gives you 3 options for gain which means internally it uses a 3 pin pot. to choose the gain for you based on the ratio of resist... (more) |
— | almost 2 years ago |
| Comment | Post #288010 |
@Carl That's good. It doesn't have to be the right leg either. It could be the hip or some other body part that doesn't move much. Then you can see what you are doing
with the lights on ;) (more) |
— | almost 2 years ago |
| Comment | Post #287952 |
Low impedances suppress high impedance E fields so very high impedance inputs do not easily attenuate. Also very low magnetic B fields can induce low current which as you know if you have a nano-amp per meter induced on a one megohm R you get a 1mV signal which is a 1000 times bigger than a microv... (more) |
— | almost 2 years ago |
| Comment | Post #288184 |
@#60854 SInce "no-load= open circuit" test, we are talking about mechanical load to a motor with zero torque load or electrical - no load when power is cut off to measure back EMF. (more) |
— | almost 2 years ago |
| Comment | Post #288183 |
Ensure there are no stored voltages on any pin when power is applied, including avoiding switch bounce.
To test an IC with power off one can apply 2Vac with a 10k to 100k series resistor to each pin to check for short circuits or ESD damage. The V-I plots may be shown in XY mode on any scope an... (more) |
— | almost 2 years ago |
| Edit | Post #288195 |
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— | almost 2 years ago |
| Edit | Post #288195 |
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— | almost 2 years ago |
| Edit | Post #288195 |
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— | almost 2 years ago |
| Edit | Post #288195 | Initial revision | — | almost 2 years ago |
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A: Over-voltage protection for device with photovoltaic cell source This IC is not well suited for the task. MPPT (Maximum Power Point Tracking) relies on matching impedance according to the maximum power transfer theorem. However, in the case of a photovoltaic array (PV), it functions as a current source with a voltage limit (Voc) and a short circuit limit (Isc).... (more) |
— | almost 2 years ago |
| Edit | Post #288185 | Initial revision | — | almost 2 years ago |
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A: What are these transformer graphs about? For R loads I is in phase with V. For L loads , V lags I up to 90 deg. For C loads, I lags V up to 90 deg. The trigonometric tangent angle is the ratio of impedance: Real to reactive. Your lectures or ref. book will give all the details. (more) |
— | almost 2 years ago |
| Edit | Post #288184 |
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— | almost 2 years ago |
| Edit | Post #288184 | Initial revision | — | almost 2 years ago |
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A: How is it possible to perform a open circuit test on a induction motor? In an open circuit test, also known as a no-load test, an induction motor is operated without any mechanical load connected to its shaft. The purpose of this test is to determine the no-load losses, core losses, and magnetizing current of the motor. General Purpose: efficiency and performance ... (more) |
— | almost 2 years ago |
| Edit | Post #288183 |
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— | almost 2 years ago |
| Edit | Post #288183 | Initial revision | — | almost 2 years ago |
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A: what should the output be for this use case of the CD4047 chip? Possibly it is damaged. Be ESD aware and do not power up with any voltage on any pins > 0.5V (Latchup failure) If raising p9 (reset) does not lower Q to logic "0"=<20% Vdd) replace the IC. No sweat, be more careful next time for handling failures of ESD etc. Most new IC failures are hand... (more) |
— | almost 2 years ago |
| Edit | Post #288036 | Initial revision | — | almost 2 years ago |
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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) |
— | almost 2 years ago |
| Edit | Post #287969 |
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— | almost 2 years 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) |
— | almost 2 years ago |
| Edit | Post #287969 |
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— | about 2 years ago |
| Edit | Post #287969 |
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— | about 2 years ago |
| Edit | Post #287969 |
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— | about 2 years ago |
| Edit | Post #287969 | Initial revision | — | about 2 years 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) |
— | about 2 years ago |
| Edit | Post #287952 | Initial revision | — | about 2 years 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) |
— | about 2 years ago |
| Edit | Post #287524 |
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— | over 2 years ago |
| Edit | Post #287524 | Initial revision | — | over 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) |
— | over 2 years ago |
| Edit | Post #287523 | Initial revision | — | over 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) |
— | over 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) |
— | over 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) |
— | over 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) |
— | over 2 years ago |
| Edit | Post #287265 |
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— | over 2 years ago |
| Edit | Post #287265 |
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— | over 2 years ago |
| Edit | Post #287265 |
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— | over 2 years ago |
| Edit | Post #287265 | Initial revision | — | over 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) |
— | over 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) |
— | over 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) |
— | over 2 years ago |
| Edit | Post #287244 |
Post edited: so what |
— | over 2 years ago |
| Edit | Post #287244 |
Post edited: plot |
— | over 2 years ago |
| Edit | Post #287244 | Initial revision | — | over 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) |
— | over 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) |
— | over 2 years ago |
| Edit | Post #287072 |
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— | over 2 years ago |