# Questions tagged [calculation]

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### What would be the AWG (American Wire Gauge) standard for my wire 1 x 0.75 rm?

I have been trying to figure out my wire gauge standard in AWG format. I bought a coil (100 meters) of wire and the info written on the package is: 1 x 0.75 rm. I understand the 1 in here represents ...
32 views

### Calculation of Power Transformers

I'm calculating transformers very roughly, with some approximate equations that I found on the internet, they are working perfectly but I'm supposing that they are oversized... They are power ...
52 views

### How do I calculate the area 1.5cm away from a LED with a 120 degree beam?

I have a SMD2835 IR LED with dimensions of 0.28cm X 0.35cm and beam angle of 120 degrees. How do I calculate the irradiation area if it is e.g 1.5cm away?
1 vote
54 views

### Crystal capacitor selection equation

So I've recently discovered that when a crystal oscillator says "20pF", it does not mean "use 20pF caps". (Despite that the design I made under that assumption appears to work.) ...
1 vote
61 views

### Determine derivative time of real PID controller

I need help determining the derivative time of a real PID controller. Above me is an ideal PID controller. In my case I have another resistor (let us say R0) before R1 and Cd serial. How do I now get ...
47 views

### Estimating junction temperature

I made a measurement using thermocouple to measure the case temperature of my TO-220 linear regulator (L7809). I'll be using degrees celsius for all temperature units and degree Celsius/Watt for all ...
1 vote
52 views

### MOV parameters understanding and capacitance

I want to add a MOV to the input of my circuit. I came across the following MOV. The specs I require will be the following: Max voltage 300V AC rms Surge voltage 1.4kV Response time 8/20us I have ...
1 vote
125 views

47 views

### How to find the right specification of LED corresponding to an incandescent bulb to replace the latter?

I have a motorcycle and its taillight had an incandescent (filament) bulb. The wiring diagram says it's specification was 18W for 12V supply. Now, I want to use an LED (or several) in its place with ...
360 views

### Finding frequency response of inductive EMI sensor

I'm building an EMI sensor and trying to understand how it's done with the Elektrosluch. Here's the full schematic but this is the part I'm concerned about: simulate this circuit – Schematic ...
1 vote
59 views

### How to find the terminal voltage of a series generator given output power and EMF?

A 12 kW, 120 V DC series generator has a series field resistance of 0.05 Ω. The generated EMF is 135 V when the generator delivers the rated load at its rated terminal voltage. The armature resistance ...
255 views

### How to get the velocity with an acceleration sensor (ADXL345)?

I want to calculate the speed with the help of an acceleration sensor, such as a ADXL345. I thought that it should be integrated, but according to the information that I have received, it seems that ...
67 views

### Why is the output of OPAMP coming as 2.239V? [duplicate]

What formula can be used to get this output? I tried using superposition theorem but the output is not coming the same. Considering V1 off and V3 at 3V : V- = 3V (2k/5.32k) = 1.128V Considering V3 off ...
43 views

### Limiting the output voltage of a boost converter

I have a boost converter TPS61288 which can boost the input upto 18v. Adjustment of the output voltage is done via a potentiometer to the feedback of pin of the converter. 18v is dangerous for my ...
65 views

### What is the current industry practice regarding the impact of current-limiting fuses on arc flash calculations?

Suppose you have a panel. The arc flash incident energy for this panel is computed based largely on the available short-circuit current (SCCA) to the panel, and the protective devices upstream of the ...
80 views

### HB100 Doppler sensor calculation

I have a question about the first circuit schematics. I calculated the second circuit's fcutLow and fcutHigh frequencies like this: f2CutHigh = 1/(2 * π * 1M * 100p) = 1.6 kHz f2CutLow = 1/(2 * π * ...
39 views

### How to calculate sum of jitter

I have two clock generator and i have connected them in series. If we assume they have jitter of x, what would be sum of jitter how can i calculate that ?
127 views

### Calculation of pull-up resistor for open-drain output - multiple loads

Link to voltage supervisor Link to AND gate I would like to drive an open-drain output to multiple (5) loads, all of the same type. I calculated the pull-up resistor range needed and wanted to double ...
1 vote
205 views

### Need help with validation of the design of a capacitance sensor array for soil moisture measurement

Product Description The device is a soil moisture sensing and analysis device that uses capacitance sensing technology to help manage soil moisture in your garden. One probe set at the bottom of the ...
224 views

### How best to perform calculation on voltage and feed output to segmented display?

I'm working on an audio electronics project that uses frequency modulation. A potentiometer will control the tempo/modulation speed, and I'd like to convert the voltage value to a triple-digit value ...
1 vote
88 views

### How to find resistance, inductance, and capacitance of a load/device

I'm planning to make a proper simulation of a circuit. Before the simulation, I need information about the load (resistance, inductance, and capacitance). Example: the load is a CPU. range of wattage ...
1 vote
2k views

### How to convert cordless tool to corded tool "properly"?

This question is the closest thing that I found similar to my needs, but it is still quite far from the answer I need. I have 2 cordless power drills, a 12V green Bosch and an 18V DeWalt. Their ...
52 views

### Calculation of tolerance of a resistor for voltage sensing

I want to calculate the tolerance of resistor accurately to run a simulation to simulate accuracy of voltage sensor. The resistor I am using is CRCW0603330RFKEA - 330 Ω from Vishay and I can't see ...
132 views

### Heating element testing - calculation

I have a 3-phase, 30 kW, 480 V AC heating element. I’m trying to utilize resistance as an aid for predictive failure. Using Ohm’s law calculation 480 times 480 equals 230400. 230400 divided by 30000 W ...
1 vote
198 views

### MOSFET thermal calculation

In my application I will use a MOSFET as an on-off switch. There won't be a PWM signal. I want to calculate the temperature rise of the MOSFET but I am confused. Continuous drain current is 100 A, RDS(...
844 views

### How to calculate the maximum current a wire can handle?

Is there a formula for calculating the maximum current a wire can conduct without melting? I found one: I = αd^(3/2) in which I = fusing current, d = wire diameter in inches, and α = a constant ...
73 views

### How to define initial conditions for complex RC circuit?

I need to calculate $U_2 (t)$. See the circuit below: Given $E$, $R_1$, $R_2$, $C_1$, $C_2$, $C_3$. The first Kirchhoff's rule: $$i_1 = i_2 + i_3 = i_4$$ Now find the all currents:  ...
90 views

### Op-amp plus diodes: resistors' values calculation

I am tasked with following: R1, R3 and R3 are to be calculated so that the diodes work in forward bias. Assuming the diodes have a voltage drop of 0.7 V and the op-amp is ideal I have calculated that ...
127 views

### Do carbon resistors generate heat in a properly working circuit?

Do resistors in a circuit generate heat based on their resistance value? Can anybody explain how resistors drop voltage without generating heat?
40 views

### Simulate powerbank's disconnected state

There is a powerbank which has (among others) an USB-A port. The powerbank can be turned on with two methods: Pushing its button Connecting a load to either of its ports In any case, the bank will ...
184 views

### What is a "charge cycle" of a lead-acid battery?

I'm trying to develop an algorithm that would roughly estimate the health of a lead-acid battery tied to an inverter backup system. It seems that my 200 Ah battery pack stays at 100% state of charge (...
325 views

### Calculation single phase and three load connected at the same time to three phase network

I have a single phase load (90 A 230 V) and 2 three phase loads (7 kW 400 V 3 phase/9 kW 400 V 3ph+N) connected at the same time to a three phase network. How the 3 phase calculations (line current of ...
142 views

### Frequency of a 555 timer

I want to use a 555 timer (as I have them at hand) to give me a 2MHz clock for an AY-3-8500. I have two questions really: While the 555 may not be ideal, is it possible? How to I calculate the ...
1 vote
49 views

### Getting Discharge Safety from a Battery

I would like to calculate the battery runtime for an ESP32, using a 18650 battery with 2600 mAh (Datasheet). When I am using a calculator such as this one, it requires me to put in a discharge safety ...
69 views

### Rewinding a 6 V DC motor and decreasing inrush current

I have a small simple 6 V DC motor and I would like to rewind its rotor. The motor has 2 magnets. The rotor has 3 poles to wind. Normally each part has 169 turns of winding with 0.15 mm2 copper wire. ...
1 vote
337 views

### Using the superposition principle when there is a current source in the circuit

At the top is the main circuit. Below that is the circuit formed by removing the 5 A current source (We remove that for using the superposition principle and this is the first step). I don't ...
108 views

### Rewriting piecewise voltage function using Heaviside?

Recently I've had an idea to create an assignment where we have low-pass filter connected to the voltage source which is described by piecewise function. I've already dealt with periodic functions ...
1 vote
195 views

### Calculating PID gains analytically on a first order plant (RL Load) - is this possible?

Edit: Just for a bit of context. I have another higher order plant model that has a derivative branch in its control. I thought I'd just implement PID control on the current in an RL load I have just ...
1 vote
274 views

### Calculating steady-state temperature for electrically heated wire

I am working on a program aimed at finding optimal parameters (voltages and feed rates) for a hot wire foam cutter. One starting problem that has to be solved before even attempting to evaluate heat ...
1 vote
121 views

### Filter coefficients and filter calculation methods

I'm trying to figure out the R and C elements for a second-order Bessel filter approximation. Unfortunately, in the below calculations the quality factor is negative, so it is wrong? (I checked by ...
262 views

### Calculating hysteresis with an open drain comparator

I have a circuit as follows which will compare an input voltage to a 2.5 V (actually 2.3 V) reference. In one of the documents, it mentions that the feedback resistor must be 100 × Rpullup. If my ...
472 views

### How do I calculate the electrical power of a BLDC motor?

I used a current sensor to measure the current of one of the motor phase lines (Iphase or Iline?), and used a voltage sensor to measure the voltage between two motor phase lines (Vline-line). With ...
1 vote
62 views

### Can the secondary voltage of this old transformer be derived?

Images are of an unknown "4808" PCB-mounted transformer. It has an open 240 VAC primary. Data: EI48 core, around 12-15VA. The center-tapped secondary is 15Ω-CT-15Ω and 1.6H-CT-1.6H according ...
438 views

### Simple circuit of 4.2 V lithium-ion to 3 V use

I have a lithium-ion battery of 4.2 V maximum voltage. I want to power a 1 W LED at 3 V. What size resistor do I need?
122 views

### 0 dB Bode plot as a reference in an academic paper

I want to compare the calculated bode plot of an inverting op-amp with the simulated one, on the 1 mHz-200 kHz spectrum. As expected, theoretically there is no stray capacitance on the circuit above, ...
391 views

### Why does 277/480V 600A 3 phase = 500 kVA and not 288 kVA?

According to an electrical engineer 277/480 V, 600 A, 3-phase is 500 kVA. I would like to understand more about why that is. I always thought 277 V x 1.73 = 480 V (and that's where 277/480 label comes ...
174 views

### How to calculate RMS noise from datasheet?

I am using an AD9833 DDS as a sine signal source for my circuit. The bandwidth will be 3.5MHz. I would like to calculate the RMS noise of the DDS for my bandwidth. The datasheet has a SNR ...
157 views

### Simple question on finding Watts and Wrms

I've done a bit of research but can't find the explanation for this problem, at least mathematically. I'm calculating W and Wrms of an audio amplifier by knowing output Vpeak and Load resistance. It's ... 