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14 views

Why is the phase margin more important than the gain margin?

I heard from some lecturers that the phase margin is more important than the gain margin. However, after searching online and in some control related textbooks I couldn't find any reference for such ...
0
votes
0answers
5 views

How to measure AC voltage without breaking circuit?

I need to measure accurate input AC Voltage for a 3-phase system but I am not allowed to break the circuit. Is there a way to do so? If so, could I ask for a brief explanation?
0
votes
0answers
56 views

Chopper active when no power?

I'm looking in how to activate a current chopper in a motor application, when there is no power available from a power supply Vin. This should prevent the motor from turning too fast in power off mode....
1
vote
0answers
14 views

Loaded transformer. Unclear origin of formula

From a homework task. Given: nominal input $$U_{1N}$$ and nominal current output $$I_{2N}$$ Also given: output voltage without load $$U_{20}$$ and short circuit voltage $$U_{KN}$$ As for nominal ...
3
votes
1answer
491 views

EAGLE for 10 layer boards with 337-ball BGA?

I have been using EAGLE for some years. The boards I have designed had the following specs: up to 4 layers 6 mil spacing densest package: QFN, 0.4 mm pitch only "ordinary" vias mainly (low ...
4
votes
2answers
442 views

Running 20 WS2812 LED strips (80 pixels each) from a single Arduino and 24V Power Supply with Buck Converters

I am building a matrix with 20 WS2812 LED Strips. Each strip is 80 pixels for a total of 1600 pixels. I want to drive them all from a single Arduino Mega board. To handle the power needs, I have a 24V ...
0
votes
0answers
22 views

CAN BUS : CAN_BUSY returned but other node recieved the previosus message

I have two can nodes in a CAN bus. node1 send messages periodically , node2 received only the first message (I can check with a CAN tool) for the first message, CAN_OK is returned for send routine. ...
3
votes
1answer
69 views

Solder balls and routing out of pad corners

I was approached the other day by a co-worker who claims he avoided routing out of corners of smd pads due to higher odds of solder balls forming. I have so far been under the impression that it is ...
3
votes
2answers
610 views

PCB design - how long should pads be made to hand solder half-vias?

I have a module with tiny castellations (half-vias) at 1.5 mm pitch. They are 0.8 mm wide and 0.6 mm deep. I am designing a breakout board for this - intended for hand soldering (not paste + pick n ...
3
votes
1answer
1k views

Is the shape of (SMD) pads relevant?

SMD pads come in basically two shapes: rectangular and rounded rectangle. Does either offer advantages? For instance for etching, or HF signal integrity?
3
votes
1answer
1k views

Eagle CAD pins with same function

I would like to design a tactile switch footprint, where there are clearly two pads and two pins on each side of the switch, but let Eagle CAD's router know that it can route to either pair of pins. I ...
-2
votes
0answers
43 views

Non-contact DC voltage (not current) detection [closed]

There are tutorials and sample circuits for non-contact AC voltage detectors (non-contact testers), but I want to know how to make something that can do the same job for DC voltage when there is no ...
0
votes
1answer
34 views

Powering 12 V LED strip from a 3.3 V esp32 including PWM

I'm developing an automation board and want the facility to PWM dim a strip of LEDs up to 5-10 amps @12 V. These are plain 2 wire LED strips, positive and negative, nothing special. My esp32 will be ...
-2
votes
0answers
22 views

High resolution compass heading sensing?

I'm building a simple GOTO telescope mount, and I've built the components for sensing precisely what angle the telescope is pointed at relative to the fixed base without problem. This gives me values ...
3
votes
1answer
67 views

Why is my small DC motor so weak with this N-type MOSFET in this simple circuit and 9V battery?

Here is my simple circuit. Any help is appreciated: When I press the momentary switch, the motor spins but it is very weak. I'm trying to figure out what I am doing wrong. When I connect it directly, ...
0
votes
0answers
22 views

IGBT conduction loss

I want to calculate heat sink thermal resistance of IGBT using parameters from a Datasheet. To do that, I have to calculate the total power loss first. It is conduction loss + switching loss. To ...
14
votes
7answers
6k views

Sensor for detecting airsoft bullet

I'm trying to make airsoft chronograph/chronometer (a device that measures airsoft bullet speed). The idea is to measure time in which bullet is traveling from point A to point B, and then I can ...
0
votes
0answers
20 views

Spark generator current limiter

I am using a spark generator for electrical discharge machining and mounted a current transducer to read the current value of the arc between workpiece and electrode. When the electrode gets too near ...
0
votes
2answers
157 views

A question about serial communication and received buffer

Using my own program in PC side, I am polling data from a device in half duplex way(like in old walkie-talkie style) through USB port. This is serial communication (Baud rate is 9600 bits/s, 8 data ...
1
vote
2answers
73 views

ADC output and voltage resolution question

I've made an attempt at this question, but the answer was wrong. Could someone please tell me where I was wrong in my calculation?
0
votes
0answers
26 views

How do processor transistor counts keep increasing, without geometric scaling?

Reading into the history of the semiconductor industry and Moore's Law, and looking at the ITRS/IRDS documents, I understand that scaling down and modern node names (7nm, 5nm etc) are now "...
0
votes
0answers
37 views

Tube amplifier with buzz

I built a tube (UK: valve) amplifier but it has one problem. When I turn it on, it starts buzzing at 150 Hz but only if I connect the audio output transformer. If I directly connect the speaker to the ...
0
votes
0answers
12 views

Signal integrity in Altium

I would like to test my pcb with signal integrity in Altium and calculate how much ps my signal spreads. I have added IBIS model for FPGA and DDR. But I don't have IBIS model for capacitors and ...
0
votes
1answer
131 views

Identifying a 20 pin laptop chip that gets very hot within seconds

I’ve been searching online to try and find out what this laptop chip does or any indication as to what would be a suitable replacement. Currently, when power is put to the board, this gets to 90° ...
0
votes
1answer
45 views

Protect RJ45 CAN from POE

I'm trying to design a PCB with CAN Bus connection with STM32 (will be using a CAN transceiver) where we're using RJ45 for the CAN port. One of the main concern is what if the user plug in a Power ...
1
vote
0answers
21 views

VHDL conversion between signed and float

I've a small IP core module which performs some operations on a float input. The module has been developed using vivado hls. As shown below, the float input of the module is taken as a ...
0
votes
2answers
205 views

How to test if a wire is connected with an Arduino

I have an Arduino to control an actuator which moves up and down reversing the current using a couple relays controlled with the Arduino. I would like to be able to detect when the actuator is up and ...
3
votes
4answers
585 views

Using the word tension in place of voltage

I was reading this paper on electrolysis and on page 2 on the third line of the second paragraph it reads: In each cell there will be a tension of 4.5 volts and a current of 25 amperes will pass; ...
0
votes
0answers
8 views

SIM808 connected Arduino for GPS

I have been working on a SIM808 for the last four days. I took all possible help from the internet but failed. Two SIM808 give errors in location finding and the HTTPS server isn't working in an ...
-1
votes
0answers
37 views

Synchronization movement for two objects [closed]

I need to move 2 objects in the same direction with synchronization. To do this I am trying to use sensors, Bluetooth and a linear servo.
0
votes
0answers
19 views

Book suggestions on de-emphasis circuits [closed]

I'm trying to understand how a de-emphasis circuit works. Can you suggest me a book giving details about this circuit?
0
votes
1answer
541 views

DO-160 indirect lightning requirement confusion

I am looking at many tvs diode online, and I wanted to know how to calculate to check if it complies with DO-160 indirect lightning surge protection. For DO-160, there are Waveform 3, 4, 5A&B, ...
-1
votes
0answers
11 views

Capacitive fingerprint sensor model format

I am trying to use one of these Adafruit fingerprint sensors from Cool Components. Background To enrol a new fingerprint into its memory, you place your finger on the sensor twice, and each time it ...
7
votes
1answer
368 views
+50

Analog Design of a Miller OTA: Am I doing it right?

So I am doing a class on Analog Design. I have to design a two-stage Miller OTA. I would like to have some feedback about my design procedure and also some help because I am stuck. My professor doesn'...
1
vote
2answers
42 views

Difference between the excitation current of a transformer and the magnetizing current

What is the difference between the magnetizing current of a transformer and excitation current? The doubt came to me when I was reading a book and it explained the real model of the transformer and ...
1
vote
2answers
64 views

Does a 220V AC fan emit much more EMI noise than a 24V DC fan?

I've been discussing this with other colleagues for some time now and we can't reach a conclusion. Also searched on internet but didn't find a good article or proof that in fact a 220V AC fan will ...
2
votes
2answers
318 views

Stepper motor torque constant and electrical constant

I'm stuck with a problem regarding hybrid stepping motors and I'm not sure where I'm wrong. I can't reconcile the torque constant with the maximum speed of a hybrid stepping motor with the following ...
-2
votes
0answers
39 views

Autostart for a humidifier [closed]

My humidifier just arrived and I couldn’t figure out how to set it up. I also bought a controller. The problem is that I can’t automate it, since when humidifier turns on it won’t start blowing. The ...
1
vote
1answer
28 views

Impedance matching method in multilevel inverter

I want to use a five-level inverter as an excitation source for magnetostrictive detection,which should be able to output a 100kHz sinwave. I learned that only if the output impendence of the source ...
0
votes
1answer
74 views

Noisy behaviour of multiplexer 74LVC1G157

I'm trying to use a WS2812B addressable LED with a multiplexer 74LVC1G157. The WS2812B uses NZR protocol comunication at 800 Kbps and each pixel scan frequency not less than 400 Hz. I have test code ...
10
votes
6answers
3k views

Why put a resistor in series with the positive terminal in a non inverting op-amp circuit?

I've tried to find the answer, but failed. Why do we add R1 in series with the positive terminal for a non-inverting amplifier? What is the best value we can assume or choose for it?
0
votes
1answer
373 views

LCD backlight LED voltage. Insignia (Sharp) Model NS-32D20SNA14

I have a TV LED back light panel from Insignia (Sharp) Model NS-32D20SNA14 I have isolated the back frame with the LED panel. The power clip is intact. Everything else is removed. Using a VOM to get ...
2
votes
1answer
75 views

What does impedance in datasheets mean?

Can anyone explain impedance in a datasheet? What does this mean: (50 uH + 5 ohm) || 50 ohm Line impedance stabilization network (LISN). Like this one : schwarzbeck.de/Datenblatt/k8124.pdf.
0
votes
1answer
37 views

Differential op-amp battery cell monitor circuit odd behavior

I'm working on a three cell LIPO battery cell voltage monitor using three differential op-amps. I had the circuit I designed below printed on a PCB and have assembled the board, but I am getting ...
0
votes
2answers
51 views

Furnace circuit ideas: constant temperature with thermocouple & heating element

I am wanting to make what we will just call a furnace that will always operate near 1800°F. I'm looking for circuit ideas or a direction in order to maintain the temperature of the furnace. The ...
1
vote
1answer
3k views

NodeMCU power via battery + battery charger + booster

I need to power a NodeMCU (as far as I know it can work with 3v3 but I use some I2C modules that need 5V so let's power everything with 5V.) I have a Li-ion battery (3.7V.) I have a TP5046 based ...
3
votes
1answer
165 views

PIC16 - MSSP Peripheral I2C Master Halting In Middle of Clock Sequence?

I'm using a single PIC16F18857 as an I2C master to talk to five PIC16F1615's on the bus. All is working great, for the most part, however, I've been experiencing a "lock up" where the master is stuck ...
2
votes
0answers
86 views

Avoiding spurious second order in a first-order RC circuit

While solving the simple RC circuit below in a particular way, I came across an interesting mathematical quirk. simulate this circuit – Schematic created using CircuitLab Using nodal analysis, ...
0
votes
1answer
41 views

Why is this combination of relay, NPN proximity sensor and LED light failing to give me expected behavior?

Forgive me as I am a ME major trying to wire up a home project (I want the light to turn on when my garage door is fully open, not partially open.) All my components are rated to work at 12V for ...
0
votes
2answers
67 views

Comparator TLV3201 Output never goes high

I've put together the circuit from the TI document Comparator with Hysteresis Reference Design using the same reference voltage to the noninverting input (Vth 2.3V - 2.7V). The Inverting input is ...

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