# All Questions

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### Erroneous oscillation voltage for LC Tank in Cadence Virtuoso

I simulated an LC tank with an ideal inductor and capacitor. The inductor's initial condition was 0 and the capacitor's was 300 mV. I expected it to oscillate with an amplitude of 300 mV, but it ...
15 views

### Mono Audio amplifier repair Help (Harman Kardon HK775) Resistors getting Hot

So I acquired an excellent vintage amplifier and started the journey of bringing him a new life. Right now I have managed to repair most of the damage and come to a working device. But there is 1 ...
• 69
10 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 ...
14 views

### Is there any way I can get Altium to calculate a correct via delay?

Via delay is different between layers, it's also different between the top and bottom layers and say top and an inner layer. Altium only provides one delay for each via, which means if you switched ...
• 64.4k
1 vote
25 views

### OPA548 not generating correct output pulse

I have created a circuit for which I would like a rail to rail output of 0 - 15V, using an OPA548 with the driving waveform generated by a microcontroller DAC powered by 3.3V. The datasheet for OPA548 ...
• 98
10 views

### VHDL: How to specify inner dimension of std_logic_vector array in port using generic?

In VHDL we can constrain the length of an std_logic_vector in port map as follows: ...
• 9,687
26 views

### Need vendor and type of wire used in headphones [closed]

I have Soundcore Vortex A3031 folding Bluetooth headphones. The issue with the headphones is that the left speaker no longer works. I have troubleshot the headphones and there is a break in the wiring ...
19 views

### How can I create a seat button that controls the same seat and a door right underneath? [closed]

It's a bit like an ejection seat, except you press a button on the seat and it reclines the seat to a downward position really quickly and opens the door quickly too all at once. Is this possible? If ...
1 vote
36 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 ...
• 12.6k
32 views

### Help identifying a female power plug (500V - 16/25A alternatiing current - 3 pins - France)

Can you tell me what kind of plug is this? I suppose it's from the 60's but absolutely not sure. May be more recent. Are there adapters to allow connecting (safely) regular "220 V" devices ...
• 249
26 views

### Buck converter for 12 VDC to 2 VDC, 50 A circuit [closed]

I want to design a circuit to convert 12 VDC to 2 VDC, 50 A with adjustable current using a potentiometer. This circuit will run for 1-4 hours each day. I don't have knowledge of electronic circuits. ...
31 views

### Is an amplifier the right choice for a heating pad?

I'm developing a heating pad controller with an Arduino. Since I don't want to use the PWM + MOSFET combination, I researched and ended up with a DAC + amplifier solution. I have a 24-watt heating pad ...
1 vote
30 views

### How do I derive the equation for current as a function of time $I(t)$ through resistor in this CLCR circuit schematic with a sine wave AC source? [duplicate]

How do I derive $I(t)$ through the resistor for the circuit schematic below? What method should be used. So far, I have tried mesh analysis for the 3 meshes using KVL but the system of equations ...
34 views

### cross coupled nmos pair

For the given circuit, I am observing the source voltage of M1 and M2 as the min of the applied voltage. Here, the current is equal in both fets. But Vg is not the same. So, both cannot be in ...
36 views

### Antenna with a copper plane

Here is probably a simple question : I have to control a high side MOSFET whose the source is connected to a point which varies between the ground, the input voltage and the half of the input voltage. ...
• 1,486
49 views

### Waterproofing for submerged connections

I've seen this question. But that's aimed at connections that see rain/spray. I've got a 4-20mA sensor which I want to submerge in up to 35m of water. The sensor, unfortunately, comes with a 5m ...
• 316
39 views

### How to improve output swing of an NMOS pixel circuit?

This is a standard pixel circuit: It works just like one would expect. When the reset signal on the gate of the PMOS is low it is conducting and charges the capacitor to 5V, then when the signal turns ...
1 vote
79 views

### Is the overvoltage protection used in this circuit a normal way of doing it?

The circuit is from a clip on YouTube. VCC is from a stepper motor generator and varies between ~0-30 volts DC. From what I understand, and please correct me if I am wrong, when the voltage gets too ...
27 views

I am trying to implement the transmit section of this GNU Radio transceiver design, documented here. This design is intended for a bladeRF SDR, but the hardware available to me is the USRP B210. The ...
1 vote
43 views

### Why AND-Latch based clock gate (ICG cell) is not reliable only when driving negative edge triggered FFs?

I'm reading the paper "A Novel Glitch-Free Integrated Clock Gating Cell for High Reliability" https://ieeexplore.ieee.org/document/8702507 It says that with AND-Latch based ICG there could ...
• 239
114 views

### What does a capacitor marked "105 | 47 μF" mean?

Attached schematic for the e-Paper driver HAT. The meaning of the yellow marked part is not clear to me. Does this mean I can replace 105 (1 μF) with 4.7 μF and use either as available? The entire ...
61 views

### Voltage in a simple LED parallel circuit

I tested two parallel LED circuits. In the first circuit, the red LED glows. In the second circuit, both of the blue LEDs glow. I know the forward voltage rose in the second circuit, but did why this ...
• 11
16 views

### CSFB service vs SRVCC service - LTE basics

I have been reading core architecture topics on LTE. In a session, I was introduced to CSFB, as a service handover, instead of the coverage handover associated with the SRVCC. While I am able to ...
• 474
250 views

### How to make a 1 H, 10 A inductor

I want to make a full-bridge rectifier with a pi filter. What are my options to make a 1 H, 10 A inductor with a small footprint?
1 vote
15 views

### Bandpass filters using capacitively coupled series resonators

I was wondering how to decide on the gap size for capacitances. Here is the figure from Microwave Engineering by Pozar: I can calculate the B values, θs and other related stuff. Furthermore, I can ...
• 11
1 vote
41 views

### Is there a concept of "rotor is blocked" feedback in a stepper motor?

I am building a mechanism to move a lever via a stepper motor controlled by a Raspberry Pi (following this tutorial) and I will be using a Stepperonline HS1715 motor. I can estimate the angle I will ...
• 441
10 views

### Reverse trilateration / multi-lateration using BLE Beacons

I'm currently working on a proof-of-concept to work out the estimated locations (longitude and latitude) of outdoor beacons with unknown locations to begin with. The solution will use a mobile ...
• 101
65 views

### Why are fuses used for appliances that are plugged into the wall socket?

Fuses are there to ensure that the device being used doesn't short circuit and overheat. How likely is it that the current from a wall socket will actually exceed its given amount of current of, for ...
29 views

### CAN Bus error frame in PWM driver

I have a CAN communication problem with my PWM RGB LED driver. I have a controller and a PWM RGB LED driver. The controller sends messages to the LED driver about what the PWM duty cycle of the RGB ...
• 145
36 views

### Can the output voltage of this variable frequency drive (VFD) be varied?

Im am looking to buy a Cutler-Hammer "Adjustable Frequency Drive" AF91AGO BF25D. I’m a bit confused even after going through its datasheet. Can the output voltage of this VFD be varied from ...
60 views

### Crystal oscillator unbalanced external capacitors

The below lines are from AVR® Microcontroller Hardware Design Considerations (AN2519). "In noisy environments the oscillator can be crucially affected. If the noise is strong enough, the ...
• 261
1 vote
53 views

### MOSFET for reverse current protection?

I have a package-integrated charging module connected to my 2-cell battery. When the charger is inactive (disconnected from input voltage), the charger eats power from my battery. I thus want to ...
1 vote
36 views

### How can I set up a reed switch/magnets on an electronic chess board to consistently detect pieces?

My goal is to build a chess board that can detect the movement of pieces on it. My current approach that I'm testing is to have a reed switch underneath each square and magnets attached to the bottom ...
• 111
43 views

### Help identifying a 5-pin (4 ground, one signal) connector

I bought a dev-kit for a piece of equipment, and it came with some optional outputs. Two of them don't have a connector, and I'm having difficulty identifying what they should be. The holes form a 2x2 ...
• 13
51 views

### Sending int16_t or uint32_t data over serial on STM32F103 microcontroller

I designed a device which includes many sensors. These sensors are constantly sending information, every 400 ms, do there are series of data which reach the microcontroller (STM32F103). I want to ...
• 1
17 views

### Minimize the quantization error of transducer and DAQ

Can somebody please let me know how to solve this problem: A 12-bit A/D converter has an input range of ± 10 V and is connected to an input amplifier with a programmable gain of 1, 10, 100, or 500. ...
1 vote
127 views

### Does this circuit exist? Frequency comparator of sorts

I need a circuit that compares two periodic pulse signals and outputs a low or high when the frequency of one is higher than the other. The two input signals are coming from CMOS 74HC devices. The ...
• 65
35 views

### How do you find the Thevenin equivalent for the circuit

I open circuited the current source and removed the power source and made it a short circuit. I cant seem to figure out how to find the equivalent resistance of the resulting circuit.
1 vote
36 views

### High Bay LED light rebuild

I've got a 200 W High Bay LED light from a friend. Its circuitry is blown up; it was connected to 380 V instead of 220 V, but it also had flickering issues before that. I would like to build it a ...
24 views

### What IMU to use for RPI or Arduino? [closed]

I have an MPU6050 but I was told it is obsolete today. It works great, however, whenever I even lightly tap a surface near it, I get noise on the gyro readings that look similar to actual motion. I ...
64 views

### Why is my oscillator way too different from simulation results?

How's going dear engineers. I hope your everything's going well. I've made a sawtooth waveform oscillator aim for about few hundread kHz. I didn't see any problems on simulation results, everything ...
1 vote
48 views

### One of my headphone sides is quieter and has less bass than the other after doing a detachable cable mod, how do I fix the imbalance?

I got this cheap headset to do a detachable cable mod to, which sounded perfectly normal prior to modding, and now the left side is much quieter and has less bass. I checked the resistance of all the ...
61 views

### Looking for a specific type of PCB mounted Kelvin test post

I don't even know where to start. I've done a cursory search/browse through Digi-Key and Mouser but haven't found anything similar. With words failing me I've drawn up a model of what it is I'm ...
14 views

I want to mount an LED Panel based display to show info/instructions to customers using a machine. I can see that there are different controller (receiver) modules available on the market, which has ...
38 views

### Via in pad without fill/cap

I am currently designing an HDI-PCB. Outer-layers micro vias, inner layers buried vias. As cost is of big concern my idea is to not fill and cap (copper plating) vias (100 μm drill ~ 75 μm finished ...
14 views

### Singular admittance matrix for large distribution network [closed]

I am working with a large-scale practical distribution network. I am trying to use the admittance matrix, but the admittance matrix is obtained to be singular. I seek help in analyzing the reason and ...
581 views

### Voltage-tunable capacitors -- how do they work, specifically those from Murata?

I'm curious about how MURATA variable capacitors work, for example, parts from the family LXRW0YV330-056. As far as I can tell, these are not semiconductor varactors, but based on some other physical ...
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1 vote
51 views

### Kria KV260 clock doesn't work

I'm trying to run a very basic blinking LED with VHDL on a Kria KV260 board. led_blink.vhd: ...
• 111
74 views

### How to isolate MCU ground with a high-side driver?

I've got an application where I am controlling a bunch of high-pressure 24 V DC valves using GPIO outputs on an ARM-based MCU. The MCU is also monitoring pressure transducers, transmitting data via ...