# Tag Info

2

The 1970's is long before I started engineering work, but at that time an oscilloscope that measured beyond 100 MHz (maybe even 10 MHz) would have been quite an expensive instrument if it was available at all. So oscilloscopes were rarely used for RF work. Furthermore, 1970's oscilloscopes were entirely analog instruments, and would provide you no ...

2

simulate this circuit – Schematic created using CircuitLab Consider the two circuits above, we want to measure R1 and R2. Assume Rw1 to Rw8 represent the wiring resistances. We know $R = \dfrac{V}{I}$ and all wires have resistance. Assume volt meters are perfect (taking no current) and that the current supplies have internal current meters. The ...

2

Welcome to EE StackExchange. I'm not familiar with Keil tools, but a quick internet search yields this, so the answer is Yes. A practical approach would be to use an GPIO and an oscilloscope. Set the GPIO high when entering you function/task and low when exiting. Connect the scope probe to the GPIO and you can measure the execution time and frequency of ...

2

There are many ways to measure capacitance, If you have a waveform generator you can either use a square wave and measure the rise time. Or a sine wave and measure the current and voltage. If you know current and voltage, you know what your load is. If the load is a capacitor, you'd also need phase information. The links below go into more depth on how this ...

2

No, you never attempt to extrapolate beyond the displayed digits of a single reading. In fact, the situation is much worse than you think. A "realistic" (as you say) ADC has several sources of error, which are usually specified in terms of offset error, gain error, and non-linearity. You must read the datasheet for the ADC or meter that you use. If you do, ...

1

Measuring a value of 1 Farad in 1 second with a DMM 1% resolution of 0.1mV and a measured value of 10 mV requires battery current when using pulse measurement techniques. Even though RLC meters use a more precise constant current sinewave at selected frequencies to measure voltage amplitude and phase shift to compute all values, they still do not go up to ...

1

Edit: The high impedance is only for the voltage measurement setting. The impedance is much much lower when measuring capacitance. According to Fluke: A multimeter determines capacitance by charging a capacitor with a known current, measuring the resulting voltage, then calculating the capacitance. They are not waiting for the RC time constant. It ...

1

Since it is a nice sine, you can also find the delay between V(in) and V(out) (assuming V(out) lags wrt V(in) by triggering on their zero-crossings, using: .meas TRAN delay_info TRIG V(vin)=0 RISE=1 TARG V(vout)=0 RISE=1 EDIT Or even better, is there a way to get the time (and use it a variable, of course) where the measure occurs on the .measure spice ...

1

If you need to measure the Y-axis at a specific time point then, for your case, you would use this: .meas tving find V(vin) at <time_value> Similarly fot the delayed voltage. Don't forget that the measurement is directly related to the resolution of the data points. By default, it's 300 points, which can give inaccurate readings. To disable waveform ...

1

A photo of a 4-terminal sensor might help. *Figure 1: A 500 A current shunt with the terminals for the high current lugs on top and small screws for the voltage sensing wires on the side. Image source: Solar Electric. Voltmeter and wires amperemeter have the same distance respect Resistance Subject. Does it works correctly if 4 wires have different ...

1

Consider a loop of current flowing between a current source and a resistor under test. The distance between the nodes at which you connect the voltmeter to that current loop defines the size of the resistor under test. The lengths of the voltmeter and ammeter wires going to those nodes do not matter. If the resistor includes any wire between itself and ...

1

Sort of... If you have the TRACESWO pin connected, you can stream limited realtime debug data to keil. One of the things it can include here is the time spent in each ISR. Also, it is most likely possible to measure performance of threads when using Keils own operating system RTX. If you own the ULINK Pro, and have the parallel ETM interface wired up, you ...

1

The Earth's magnetic field is about 30uG at the equator and 60 uG at the poles. A small solar flare can cause 200uG. For RF measurements you must also consider the power and Bandwidth of your magnetic fields to make reasoned comparisons. 1 T = 10,000 G So 1 mG= 0.1 uT

1

A DSO is linear amplitude vs time usually high impedance. A VVM is linear or logarithmic with amplitude and linear phase vs f and usually 50 Ohms and measures over a far greater dynamic range and better accuracy in phase vs freq. and much wider dynamic range of amplitudes. Selection depends on the impedance, amplitude and accuracy of your measurements. ...

1

Your calculation is correct but the result is not really the uncertainty of your measurement, it's only the maximum instrument error. If you want to calculate the uncertainty following the ISO standard you need to go a bit further. In this document you have a very good example: Fluke DMM Uncertainty Calculation If you follow the example presented with ...

1

If accuracy is ±0.0030% of a 100mV range, ±0.0030% * 100 mV = ±0.00003 * 100 mV= ± 3 μV So if your example was 0.1 mV = 100 μV ± 3 μV Accuracy can be specified differently as a % of reading with a number of counts. It can be defined in terms of each part of error; gain, offset, non-linearity normally examples like yours are expressed in parts per ...

Only top voted, non community-wiki answers of a minimum length are eligible