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3 answers
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"Inverting op-amp" circuit calculations using the general feedback formula

I managed to derive the "non-inverting op-amp" circuit using equations from the general formula of negative feedback. Unfortunately, I could not calculate the "inverting op-amp" ...
slimcolt's user avatar
  • 135
1 vote
0 answers
36 views

How to calculate values for current and voltage limiting resistors in variable power supply?

I have an assignment, where I have to calculate the values for a current limiting resistor (R3) and a voltage limiting resistor (R14) for a variable power supply. The input voltage to the circuit is ...
Magnus's user avatar
  • 11
0 votes
3 answers
86 views

How to calculate current limiter resistor when voltage regulator is involved?

I'm designing my first PCB and I'm not sure if the diagram I found on a datasheet is complete. For what I have read, there should be a resistor between R1 and the transistor Tr1. I have followed this ...
Waripolazo's user avatar
0 votes
1 answer
46 views

Parallel circuit calculations [closed]

This is definitely a very simple question for those in this community but I’m in a bit of a jam here. I did a lab where we simply measured the current, voltage and resistance on a low voltage trainer. ...
Aidan Patten's user avatar
1 vote
2 answers
113 views

Fundamentals of electrical circuits. Practice problem 16.13 Network Stability [closed]

I have this question from my Electrical Electronics textbook. After repeated efforts I still can't manage to solve it and the textbook doesn't provide enough information to be able to solve this ...
Olalekan Adekanmbi's user avatar
0 votes
2 answers
141 views

LED circuit: Need to understand how to calculate

I'm facing to following problem: I need to turn on 5 LEDs (2 V, 30 mA) in series from a 12 VDC power supply using a MOSFET (2N7000G in this case). To calculate the resistor this formula was used: 12 V ...
SkePsis's user avatar
  • 67
1 vote
1 answer
83 views

Parallel resistors circuit: remove random resistors and from the total resistance know which were removed

This is more of a mathematics question than an electronics one. With this circuit, I want to know the state of the switches above the resistors, without looking at them. The use case is that I have a ...
Wer Bn's user avatar
  • 111
3 votes
3 answers
163 views

Base resistor on BC817-40

There are base resistor calculators and multiple questions are answered on the subject of base resistor calculation. However, the BC817-40 I am using from MCC is showing two different gains (HFE1 and ...
Gailu's user avatar
  • 33
1 vote
1 answer
97 views

Differential amplifier, calculation of differential and common gain

Maybe someone can help and knows how to calculate the differential gain and common-mode gain in a differential amplifier. Will the formula for differential gain be Ad=Rc/2Re, i.e. in my case 50/40=1....
grigoriii's user avatar
0 votes
1 answer
72 views

Voltage regulator circuit calculations (zener diodes, transistors)

The circuit given in the following Figure is a voltage regulator which is used to supply a constant voltage. It has the following properties: Vin = 20V, Rs = 1 kΩ, R1 = 200 Ω, R2 = 800 Ω, R3 = 2 KΩ, ...
NonComposMentis's user avatar
0 votes
1 answer
81 views

Bypass Capacitor

This is a very general question, how to calculate the capacitance needed for a bypass capacitor? Is there a rule of thumb because I usually find values like 0.1uF for high-frequency bypass caps.
Bananabread's user avatar
0 votes
0 answers
28 views

Six LED Strips 24 V with battery - runtime?

I bought six 250 cm long addressable 24 V LED flexible tubes from Sunliteleds.com According to the producer it uses 28.8 W/m 2.5 meters x 28.8 W = 72 W / Strip So if I use a battery with 10.4 Ah at 24 ...
pixelcrash's user avatar
0 votes
2 answers
72 views

LED Matrix Calculation

I am new to electrical engineering and want to build an LED 4x4 cube. The schematic is below. I need to know how much power I need if all LEDs are on at once. The LEDs I use use an average of 2.8V and ...
Finn's user avatar
  • 13
0 votes
0 answers
46 views

How can I calculate the right capacitance value if I have voltage, current, watts and power factor?

I have test results. As we can see, there is a lot of information about voltage, current, watts, capacitance, etc. I have tried to calculate the capacitance value (Cap./Ind.) in the picture, but I ...
user16266657's user avatar
0 votes
0 answers
49 views

Calculating JFET stats for a constant current source [duplicate]

I need to find a constant current source for a variable LM317 current regulator (schematic below), and I would like to know which JFETs to use. Can somebody let me know how much current I need and ...
Klumpy7's user avatar
  • 382
0 votes
1 answer
60 views

Calculation of unity level (0dB) after gained VCA

Basically I'm controlling a VCA (AS2164) with my Arduino through a 10 bit DAC. All is working well. The VCA output is then gained x 3.3 though an op amp, which in my calculator gives a 10dB boost. The ...
Jesper Kragh's user avatar
0 votes
1 answer
99 views

Can I calculate beta by using the quiescent point and a voltage divider?

How can I calculate beta with only the data in the image? Q is the quiescent point. I've tried with the basics Vcc formulas, but since it doesn't provide any value for Vcc I could not proceed.
Enzo's user avatar
  • 3
0 votes
0 answers
94 views

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 ...
Md. Imran Hossain's user avatar
0 votes
0 answers
35 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 ...
samuel mattio's user avatar
0 votes
2 answers
57 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?
HJR's user avatar
  • 1
1 vote
2 answers
129 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.) ...
Erhannis's user avatar
  • 177
1 vote
1 answer
100 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 ...
helphelphelppp's user avatar
2 votes
0 answers
57 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 ...
user139731's user avatar
1 vote
1 answer
147 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 ...
JoeyB's user avatar
  • 2,257
1 vote
1 answer
351 views

Calculate current flowing through each of the resistors in the following circuit: [closed]

I'm not sure how to go about this, but the answers are below
Xeocas's user avatar
  • 13
0 votes
1 answer
49 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 ...
user39154's user avatar
7 votes
2 answers
407 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 ...
Andrew Li's user avatar
  • 215
1 vote
1 answer
148 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 ...
boseliker's user avatar
3 votes
3 answers
643 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 ...
Ho3ein H K's user avatar
0 votes
0 answers
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 ...
user642000's user avatar
0 votes
1 answer
80 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 ...
DrakeJest's user avatar
  • 897
4 votes
0 answers
110 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 ...
Stephen Collings's user avatar
0 votes
0 answers
144 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 * ...
Grammerking's user avatar
0 votes
2 answers
288 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 ...
Matty's user avatar
  • 207
1 vote
1 answer
221 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 ...
Tim Cerka's user avatar
  • 109
4 votes
2 answers
226 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 ...
Gabe Fernandes's user avatar
1 vote
1 answer
191 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 ...
Epe's user avatar
  • 33
2 votes
3 answers
6k 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 ...
virolino's user avatar
  • 449
0 votes
1 answer
88 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 ...
Alison's user avatar
  • 347
0 votes
1 answer
958 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 ...
Sans307's user avatar
1 vote
4 answers
848 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(...
Yunus Emre Üzmez's user avatar
0 votes
3 answers
3k 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 ...
Maciej Dałek's user avatar
0 votes
1 answer
93 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: $$ ...
maestro's user avatar
  • 179
0 votes
2 answers
114 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 ...
eenewbie's user avatar
0 votes
2 answers
138 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?
user2465357's user avatar
7 votes
2 answers
543 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 (...
Davcroo's user avatar
  • 71
0 votes
1 answer
772 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 ...
Engineer's user avatar
0 votes
2 answers
254 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 ...
Simon's user avatar
  • 3
1 vote
1 answer
52 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 ...
level-up30's user avatar
2 votes
1 answer
104 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. ...
Elentronics's user avatar