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4 views

Series identical power supplies

Recently I made a thread about parallel supplies, however my helper fried one of them... Wonderful. So I got myself 4 of the famous DPS-1200FB-1 12v 100A power supplies. So I am an electronics noob, ...
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1answer
10 views

Fourierspectrum of the output voltage of an real inverting amplifier

First a quick descripton of my circuit: The inverting amplifier amplifies by 20dB, the input voltage is a sinus signal with the Frequency 10 kHz and the peak to peak voltage is 200mV or 10V. The used ...
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1answer
17 views

Why do the voltage measured across a DC motor drop when its turned on

In my experiences with DC motors there is thing that i have noticed where in the voltage measured across the motor when it is off is higher compared to when it is on. Why is that? I have always paid ...
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1answer
26 views

Can I use a PWM controller to control the speed of a motor?

First off, I’m starting electronics as a hobby so excuse my lack of knowledge about electronics in general. As a staring project, I was going to try and make a magnetic stirrer to use in a chemistry ...
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0answers
23 views

DIY UPS for Home Automation/Energy Management system

I am looking for some thoughts on a DIY UPS circuit. I just replaced the batteries on my camper and I have (2)Trojan T145 (230Ah) 6 volt batteries. Since I have them sitting here and they are looking ...
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0answers
12 views

Can LTSpice used in command line on MacOS?

Can LTSpice used in the terminal by a command line? Is there any example there ? I only saw examples in Windows OS How would simulating a circuit file using LTSpice using terminal in MacOS? (like ...
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0answers
55 views

Help me identify this burned component [closed]

im a big noob and learning stuff about electronics and accidentally burned a component on my laptop motherboard. The burned component ends with letter "t", just as the neighboring one which has "42t"...
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1answer
41 views

Thevenin Equivalent Circuit Question

I'm reading from Hayt's Engineering Circuit Analysis and, in it, it says that Two other methods have a certain appeal because they can be used for any of the three types of networks considered. In ...
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0answers
24 views

Capacitor multiplier with mosfet and digital control

I want to use a "capacitor multiplier" to reduce switching regulator ripple after an LC filter and before feeding it to the linear regulator, below circuit is what I end up with after some research: ...
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0answers
68 views

How to filter signals which are very close to each other in frequency?

I think the diagram explains the situation. The filter block should distinguish these three frequencies from each other. One requirement about this block is: For each output waveform, the other two ...
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1answer
42 views

What is meant by power well in IC terminology?

Intel PCH Datasheet refers to power wells: Core well, Suspend well, Active Sleep well. Is power well same as power rail/power plane? Does it have any connection with p-well or n-well in IC ...
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1answer
40 views

Rising edge detector negative pulse emitter - how to prevent firing at power up?

The point of this circuit is to allow rising edges to send a negative pulse to a 555 timer. C1's purpose is to allow rising edges to trigger a positive pulse which in turn connects output to ground. ...
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1answer
31 views

Radio receiver and deep sleep?

Context: I have now a working module based on an ATtiny45, a push button, a superheterodyne radio transmitter, and batteries. By using "pin change interrupts", I can make the ATtiny "deep sleep" ...
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0answers
25 views

Buck Converter - Calculating Line and Load Regulation

I have a buck converter with a PWM circuit and Control Circuit in LTSpice. I'm wondering, how do I simulate values for load regulation and line regulation? I was thinking for line regulation I could ...
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2answers
49 views

Shift Registers for generating codes

can you explain me in simple words how does a linear feedback shift register work for generating a code? Consider for instance this scheme: If I have understood it correctly, each block is a D Flip ...
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1answer
24 views

determine the values of a and n leading to the optimal curve fit

The current, I in mA, in a circuit is measured for various voltage values V in volts. If the law connecting I and V is I = aV^n, where a and n are constants, draw an appropriate graph and determine ...
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1answer
29 views

How to calculate voltage drop on lead acid battery

I have a motorcycle with an alarm on it. I left the bike for 5 days and the battery dropped from 12.5v to 11.9v a 0.6v drop. The bike still started. 12v battery 9.5 Ah sealed lead acid battery I ...
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0answers
8 views

Fitting a BQ24650 based MPPT charge controller to a permanent magnet generator wind turbine

I am investigating MPPT charge controllers modules for wind turbines. I came to the conclusion that my MPPT controller design investigations are more fitted to wind turbine MPPT than solar. I need ...
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0answers
16 views

Node voltages in a n input NAND gate in dynamic CMOS logic

Consider a regular n input dynamic logic CMOS precharged to VDD during precharge phase (CLK=0). All the n-1 inputs are set to VDD as well; i.e. V1-V2=V3=...=Vn-1=VDD. Vn=0. At evaluate phase (CLK=1), ...
1
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1answer
62 views

Why are orange diode lasers still not common although orange LEDs have been around for decades?

Nowadays you can find lots of cheap laser diodes emitting light at wavelengths such as 405, 450, ~640, ≥780 and, since recently, also ~520 nm. But it's really hard to find a laser diode emitting at ...
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0answers
22 views

How to use output of FullWave Rect to an opamp without difference amplifier

Hi I need to convert my AC signal to DC one and I achieved this by doing FullWave Rectifier with a parallel capacitor as in figure below I know that Voltage difference between tips of the capacitor ...
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0answers
25 views

Schmitt Triger Simulation in LTspice

I got a homework question as follows: I was able to create triangle wave but I am having problem with the output wave. It is not exactly a square wave. What am I doing wrong ? Simulate the ...
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1answer
28 views

Grabbing EMF meter magnifies signal 10fold

I have a Tenmars tm‑195. Holding it in my hand arm's length, still, I read \$2 \mu W / cm^2\$. In exactly the same spot, without me holding it, I read 10 times lower, \$0.2 \mu W / cm^2\$. I can ...
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2answers
33 views

Magnetic field of 2 solenoids

If I wound 2 solenoids in opposite direction (wound into each other like in the photo) will I cancel the magnetic fied ? Or did I made it stronger ? Is it better than having a twister pair cables, ...
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0answers
23 views

Eagle project creation problem

When try to create a project on eagle there show a error. I can not create any project or can not save any schematic file.
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0answers
46 views

Orientation of mechanical relay switch in fighter jets

The fighter jets can have several g's of vertical as well as horizontal force on them when they take off or do maneuvers. Let us say I need to place a mechanical relay switch in it. How should the ...
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1answer
36 views

SWD on self-made STM32L433 board - “Error: No STM32 target found!”

I made my first PCB with an STM32L433 and I have it working via dfu-util to program it. But now I want to debug the code I write for it so I was looking into SWD, ...
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0answers
16 views

Strange behaviour observed while SMPS testing:

I was doing load regulation test for the converter NB679GD. The converter supports input voltage from 5.5 V to 28V and produces a regulated output of 5V. Load is varied from 0.01A to 8A. The test was ...
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2answers
39 views

datasheet register address is not in HEX?

I am reading the this datasheet for the CAP1188 touch sensor and can't figure out what these "register addresses" in the far left column mean. I am used to seeing HEX addresses in datasheets such as <...
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1answer
20 views

Parallel on-board bus and Serial off-board bus [closed]

Let us say I need to route a 16-bit data bus between an MCU and a Memory chip both of them are on the same PCB board less than 10 cm apart from each other. Let us say the bus speed is more than 50 MHz....
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0answers
22 views

How to detect that signal suffers from high speed affect corruption using scope?

As far as I am aware, when connecting two PCBs together to transmit high speed signals one should make use of HSMC interface or use 50ohm terminated connectors with coaxial cables. However, lets ...
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0answers
20 views

Can anyone explain how to solve this circuit for V and I at the given locations? [closed]

I was given this circuit and need to solve it for the current and the voltage at the indicated locations. Can anyone explain the method to do this?
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0answers
15 views

Small Signal model of darlington pair with resistor

Im trying to create a small signal model of a circuit with a darlington pair in it. The circuit is the one in the image below. I have managed to do this small-signal model but i feel it is a little ...
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0answers
16 views

How to understand if its a secord order transient circuit problem?

For first order circuits(namely RL and RC) we have a time constant $$ T= \frac{1}{RC} $$ or $$ T= \frac{L}{R} $$ to figure out if the problem is about transient analysis. How do I realize if its ...
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2answers
23 views

Compatibilty between GPRS and LTE modules and networks

I summerized the question for ease as follows: Lets say we have an LTE module under the coverage of an old base station like 2G with GPRS. Will the LTE module work? Lets say we have a GPRS module ...
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1answer
48 views

Low pass LC filter goes “wrong” with capacitive load

I have been experimenting with this circuit: simulate this circuit – Schematic created using CircuitLab Vin has a lower frequency ripple of 2V and a high frequency (switching?) noise of 6.5V. ...
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0answers
31 views

DC circuit, equivalent sources

Find equivalent current and voltage source for this circuit: I think that we can ommit the part of the circuit with capacitor and treat it like a break in a circuit. And Then im really confused on ...
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1answer
27 views

Usb charge circuit blown fb1 [closed]

USB port circuit fb1 ferrite bead blown. Question is can i replace this and what size should it be it’s about 2mm x 1.2 I’m quite ok with a soldering iron many thanks in advance Ps I have got some ...
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0answers
46 views

Why this contact has some leakage voltage?

I have a relay circuit ,the input is 30V DC . Relay switching is work well(output has 30v dc while relay switch from NC to NO). But relay output(P2) has some voltage without relay switching from NC ...
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0answers
21 views

Rs and Rd in series in MOSFET circuit?

Can we consider Rs and Rd to be in series? That is, is the equation ID = (Vdd)/(Rd+Rs) correct? What is confusing me is that they have the same current, but there's a voltage drop across the drain-...
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0answers
31 views

How does a traditional CC/CV circuit work?

I went through an application note from Texas Instruments referenced as snva829 ( the link http://www.ti.com/lit/an/snva829/snva829.pdf page 2 and 3) where they have discussed superficially the ...
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0answers
18 views

Why wont this TV PSU turn on with the PS-ON pin? [closed]

I have an old TV that doesn't have a digital TV tuner, so I'm swapping a board from a different TV into it. I already have the LVDS cable rewired and it works great with both TV mainboards powered on. ...
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1answer
16 views

Can I use solid state output and relay output with the same components?

So I have a OTB1E0DM9LP Schinder Electric I/O distributed module and I want use it'output to control some 24v electro-valve's and some 24V contactors. The module have 2 Solid-state outputs of 24V 0....
0
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1answer
36 views

AC line detection, with or without optocoupler?

If you want just to detect AC line (220VAC) existence using micro-controller, does using optocoupler has any advantages rather to simple RC circuit? Even if you want to meet EMC/EMI/Industrial ...
1
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1answer
42 views

How to solve the (b) circuit?

In circuit b there is a Zener, LED and transistor the voltage of base I assume is 12 V - 6.2 V = 5.8 V so I guess Ve is Vb - Vbe = 5.8 V - 0.7 V = 5.1 V but I can't guess the current which is passing ...
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0answers
14 views

STM32 __HAL_TIM_GET_FLAG vs. __HAL_TIM_GET_IT_SOURCE and how doing without (CMSIS)

I'm trying to configure a timer (on STM32F0 but I guess it's the same on the rest of the STM32F family) with Output Compare to get an interrupt for two different actions at two different time ...
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0answers
45 views

Create an oscillating current with just npn transistors?

Though I drew something down, I need to know if it's really possible to make a very high clock pulse from just a few transistors, and I need to know how? Please don't suggest piezoelectric methods... ...
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0answers
24 views

What is the pad-etching process in standard CMOS fabrication process

What is the pad etching process? Is it possible to etch to the bottom metal layers or vias in standard CMOS fabrication?
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0answers
24 views

Using batteries to power op amp

So pretty much I have a ~4.5V power supply from 3 AA batteries, that I want to power an op amp (LM358P). The reason I'm doing this is so I can boost the AC signal from a piezo sensor, the problem is, ...
2
votes
1answer
48 views

Passive bandpass filter simulation gives wrong cutoff values

I'm simulating the following passive bandpass filter in LTSPICE, and can't figure out why my calculated cutoff values don't match the -3db values in the simulation. Here's the circuit I'm simulating: ...

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