Questions tagged [instrumentation]

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2
votes
5answers
256 views

Choosing a digital oscilloscope for a self learner [closed]

I'm about to start a course about electronic interfaces. My intention is to learn to debug hardware by doing measurements etc. with oscilloscopes and multimeters. According to the course, the ...
0
votes
2answers
83 views

exceeding an analog ammeter printed scale

I have a ~$10 DC ammeter I mail ordered however long ago, on the display is printed Dagatron 7203 and on the lower right side of display is an upside down U ...
20
votes
13answers
7k views

Why only sine waves?

I have already read a few EE texts where a sine wave is often seen. Why is the sine wave often used as a test function for a circuit or a system? Why don't we use any other signal instead of sine? ...
0
votes
0answers
23 views

Can these SPICE models be used to compare single ended versus 4-20mA current signals?

I want to compare the environmental or common mode interference effect to current vs voltage signals by using two different transducer types current and voltage respectively. Below I compare two ...
0
votes
2answers
51 views

Instrumentation Amplifier Reference Node - Integrator vs Buffer

When looking at INA topologies (lets take AD8220 for example) I see examples of integrator or buffered resistor dividers used. What are the disadvantages of using an integrator? Both typologies ...
7
votes
1answer
116 views

Purpose of resistor across op-amp inputs

The following (from TI app note slaa414a) is an active bias-T that sums the AC and DC inputs to drive a load for the purpose of testing PSRR. What does the 100 Ohm resistor across the inputs do? Both ...
0
votes
1answer
41 views

How to obtain a high precision mV signal within a specific interval using a variable resistor?

I want to design a circuit which outputs a signal ranging from 0-70 mV using a variable resistor ranging from 80.51 Ohm - 183.05 Ohm and a supply voltage of 12 V. My idea so far has been to make a ...
2
votes
2answers
47 views

Questions regarding DC-DC converters powering transducers

Several of these transducers requires isolation as recommended here in their manual: The transducer models are uni-polar 0-10V output which require 24VDC power supplies. So at the moment there is a ...
0
votes
1answer
38 views

polarised condensor microphone

Sir/Madam, Kindly explain how is the following equation derived for the polarised condenser microphone? The output voltage V0 fed from the microphone to the preamplifier will be how is it derived? ...
2
votes
1answer
94 views

How to extract the switching noise component for this signal data?

A servo accelerometer when powered by batteries has a clean output, but when used with this SMPS supply its output seems like have switching artifacts from the power supply(the datasheet says its ...
1
vote
1answer
47 views

measuring ac voltage drop across a resistor with a solenoid in series with it

I wanted to measure the phase difference between the current (magnetic field due to the solenoid) and the system response. I am doing this by measuring the voltage drop across the resistor in series ...
-1
votes
1answer
35 views

Custom Test Fixture for LCR meter

I've designed and built a custom test fixture (based on Keysight's 16047A) to be able to measure multiple pin capacitors. When testing it to compare both fixtures (the custom and the original), I ...
1
vote
1answer
101 views

Instrumentation Amplifier Connection Problem

I am trying to build a circuit capable of measuring ECG signals following the scheme attached. Since AD623 was out of stock, i ended up buying something like this: https://www.arduino-tech.com/cjmcu-...
3
votes
3answers
122 views

Microvolt to milivolt/volt amplifier with common components

Suppose one has access to common components and gear only : basic milivolt multimeter, badly regulated supply, linear regulators, 1% resistors, common BJT/FET, voltage references like LM431 or zener ...
0
votes
0answers
120 views

measure 4-20 mA and also power from loop powered

we know to give a command to an actuator in instrumentation we use 4-20 mA loop power. for reading this 4-20 mA I used the circuit below.so the problem is if my circuit only consumes 3mA, how should ...
1
vote
1answer
32 views

Measurement range versus calibration in electronic instrumentation

I need to monitor temperature between -15°C and +40°C. The transducer(Pt100 probe and R/I transmitter) can measure between -25°C to 72°C. But I need the temperature transducer to be calibrated by an ...
-2
votes
1answer
92 views

Definition of \$ \frac{mm}{Ampere}\$ (unit of current sensitivity)?

I want to know how \$ \frac{mm}{Ampere}\$ (which is the unit of current sensitivity of PMMC instruments) is defined? i.e, How \$ mm \$ is defined in terms of \$ degrees\$ ? For eg.: \$ \frac{rad}{...
0
votes
1answer
74 views

Questions about grounding points for an analog signal transmission

I'm planning to implement the following circuit I have drawn. But because there is no SPICE for such components I couldn't verify or test any overall workings. From left to right I will first ...
1
vote
2answers
233 views

Using a fully differential amplifier as a differential ADC driver

Regarding my previous question, I decided to use a “fully differential amplifier” to obtain a voltage gain of 10. The source and ADC are also differential. The source is unipolar and its output ...
0
votes
2answers
41 views

measuring resistance on hv transformer

I need to verify the resistance on a HV transformer that receives 208v single phase through terminal 1 and 2, or 240v through terminal 1 and 3 and delivers 4000v through terminal 4. As per the ...
0
votes
0answers
139 views

1. order system Gain

I have been assigned a task and I am having trouble finding the gain K. Here is the task: To the time t = 0, there is put a step at 3. Find the gain. Find the time constant. Find the time delay. ...
5
votes
4answers
1k views

Why do LCR meter manufacturers give the details of measurement frequency to us?

When you want to purchase a DMM, more probably you don't see at what frequency the DMM you considered would work, but in the situation you're considering to purchase an LCR meter, manufacturers give ...
1
vote
2answers
70 views

Problem understanding impedance measurement device accuracy format

I am reading the datasheet of an impedance measurement device. Its accuracy is listed as '±0.4% rdg. ±8 dgt.'. What does 'rdg.' and 'dgt.' mean? And how should I interpret the accuracy? The device is ...
0
votes
2answers
38 views

Signal response and settling time graph analysis

I have come across a datasheet of an instrumentation amplifier. I have a difficulty in understanding the signal response vs settling time graphs. Can someone please explain figure 28(page 10) of the ...
4
votes
3answers
452 views

How to make repeatable Op-amp amplifier circuit

I did a simple op-amp based 100X gain single ended circuit. I tried to order 100 IC's and manufactured them. But found that out of 100 only 60 devices have same and expected baseline. What could be ...
0
votes
1answer
81 views

Trouble with instrumentation and simulation of the common-mode response of a filter

I have been struggling to obtain the Bode plot of common-mode response of a filter. I first simulated it using LTspice, then I used a USB network analyzer. Both do not match each other and to the ...
1
vote
2answers
798 views

For SCPI programming in python, Is it necessary to install a NI-VISA back-end if you are trying to iterface with a non-National Instruments device? [closed]

[background/context] hello, I am trying to learn to automate measurement devices using SCPI commands, but instead of using Labview I decided to go with python. I have played around with SCPI commands ...
0
votes
2answers
70 views

Appearing voltage when connecting different grounds

We have designed instrumentation equipment. When several instrumentation units are connected their grounds must be connected. The first proposal was to connect the GNDs by cascade topology. But we ...
2
votes
3answers
1k views

LM324 instrumentation amplifier gain and offset problem

I want to translate a Pt100 RTD to a 0-10V range, to be read by a PLC. I designed a circuit (instrumentation amplifier) using the LM324 op-amp. It is powered using a single 12V supply.The resistor ...
0
votes
1answer
291 views

How does the Zoom ADC exactly zoom in (Practically)?

I am trying to understand the actual working of this specific Zoom ADC (diagram below), which is a 2-Step ADC with coarse (SAR) ADC and a fine (Sigma-Delta) ADC. I understand it theoritically but ...
0
votes
0answers
257 views

Measuring current using ACS 712 with NI DAQ 9215

I am trying to measure current from Ignition coil(12V, 4.5A). i used arduino to measure current. And it worked good. And i connected the ACS712 signal pin to NI DAQ 9215. At zero current the output ...
1
vote
1answer
365 views

Problem encountered while amplifying load cell signal with LM358

I have an S-type load cell to measure weight up to 100 Kg. Its datasheet mentions 3mV/V against full range and excitation voltage. When no weight is applied, the voltage is 9.9 mV (Excitation is 10 V)...
1
vote
1answer
52 views

Using a scope for an instrumentation and mains earth

When I make a measurement using a scope and observe transducer voltage output on the scope screen, I want to eliminate the noise as much as possible which is due to device and scope coupling or common ...
1
vote
1answer
61 views

UPS for 1.1kW system [closed]

We have 3 motors each 0.37kW, they are now running on mains power, sometimes mains power cutoffs/fails, in that case we want the motors keep running. The motors are controlled by a PLC which do not ...
0
votes
3answers
80 views

How to measure tilt on a dynamic device?

I'm trying to instrument a vehicle component. I want to measure a component's angle during a drive cycle. The component has a single degree of freedom, it has a fixed axis. I'm trying to figure out ...
0
votes
1answer
50 views

Testing short in circuit

I think it is a very simple test to perform, but I do not know the correct equipment for this. I just have a basic LED circuit, resistor before LED, but I want to test a short in parallel with the ...
1
vote
0answers
60 views

How to measure gasoline:oil ratio for 2-stroke motor?

For some reason I am obsessed with instrumenting my small fishing boat. I'd like to have a continuous measurement of the gasoline:oil ratio in both my main (70HP) motor and kicker (7.5HP); I have a ...
0
votes
1answer
751 views

Derivation of the transfer function of a instrumentation amplifier

I've just been really frustrated because I've been trying to understand this information online about how the transfer function of an instrumentation amplifier is derived. It would be really helpful ...
1
vote
3answers
637 views

Current Transformer (CT) and Potential Transformer (PT) Sensors - How to Measure Electrical Power Usage?

I am not from Electrical Engineering background and so, does not have much idea about how energy power meters work. I want to measure electrical power usage of a three-phase induction motor. So, I ...
1
vote
1answer
168 views

How to shield a battery powered instrumentation with USB interface?

I would like to ask for advice on shielding the following setup. I have a measurement target sitting inside a Faraday cage, connected through a shielded cable to a measurement circuit. The cable ...
1
vote
2answers
294 views

op amp DC gain drop

I got a really simple circuit, it is a voltage follower in cascade with an inverting amplifier. The input of the voltage follower is a current to voltage converter, measuring nanoamperes with a 1 M ...
0
votes
1answer
79 views

How to obtain current-voltage trace using a picoammeter?

I am designing a probe where ions will finally impinge a metallic collector. The collector is connected to a picoammeter to measure the collected current. How can I finally obtain a current-voltage ...
0
votes
2answers
148 views

Need help with instrumentation amp behaviour

I was wondering if someone could help me understand why this instrumentation amp isn't working the way I think it should. The amp is an INA155. My intention is that at if a voltage (positive or ...
1
vote
1answer
279 views

Higher Order Filters

I am designing a signal conditioning circuit to remove all frequency under 20Hz for some EMG measurement. I have several questions about the circuit design: For the instrumentation amplifier, should ...
4
votes
2answers
2k views

ECG circuit Pre amplifier

I am in the process of designing an ECG circuit to detect heartbeat abnormalities. I have two question regarding the AD8220 datasheet: What is the function of the 2.2pF, 10pF capacitor, 10k, 15k ...
0
votes
1answer
55 views

A question about max TTL input of a converter device

I have a programmable f/I converter which can be modified for various types of inputs and outputs. They have also a more detailed manual. I read them and learned how to configure and set this device. ...
1
vote
1answer
260 views

What does it actually mean by that a transducer has good dynamic response?

One of the basic requirements of a transducer is that it has good dynamic response. I am having trouble understanding the meaning. My textbook says: The output of the transducer should be faithful ...
0
votes
2answers
233 views

Proportional control of 0-12 V DC power source with 0-5 V DC analog signal

I am taking an instrumentation class and for our final project we are modeling a ventilated barn, to do this we want to vary the speed of a 12 V DC 0.35 Amp fan. To control the fan we are sending a 0-...
0
votes
2answers
32 views

Transmitter max output when checking ohms in parallel

To make my question simple and easy to understand I am giving an example below. I have an RTD (platinum 100) which change resistance with increase in temperature, for checking that rtd is showing ...
1
vote
2answers
394 views

Is there any analog meter with the needle capable of a full revolution?

Is there any analog meter with the needle capable of a full revolution? I have always seen only instruments where the needle can rotate only a fraction of 360 degrees, for example in the following ...