All Questions
174,188
questions
-1
votes
2
answers
151
views
What is the name of this D-shaped electrical component symbol?
I believe that there is a missing component in the highlighted area.
What is that component?
I have done some research and found that symbol corresponds to a transistor but I'm not sure what type of ...
0
votes
0
answers
69
views
Circuit to measure RF signal bandwidth?
I'm designing an RF circuit which needs to classify signals into two categories according to their bandwidth. The signal of interest will be either
a) A series of frequency hopping packets with narrow ...
1
vote
2
answers
175
views
Will this voltage divider keep my MOSFET on? [closed]
I'm hoping to use a voltage divider to supply voltage to the gates of some MOSFETs. The divider will be scaled at a voltage ratio of 1:10 to a high voltage battery that will discharge from 240 V to ...
0
votes
0
answers
45
views
Using resonators to phase-in a PWM
I'd like to have a constant PWM signals, much like this:
Wherein the blue trace have centered it's hi at the 0 of the fully rectified AC & the red have centered ...
0
votes
2
answers
34
views
Select PSU for 12V DC water pump
So I bought me this cheap 12V DC water pump for a garden project. Then I used a wall-wart type switchable PSU (similar to this one) to do a quick test. Works, but it has problems:
The pump is rated ...
- 277
1
vote
1
answer
53
views
555 timer charge pump with feedback
In the circuit I am working on there is a requirement to create 30V DC source for a very light load (couple of mA max). I am aware that there a specialized ICs that can do that but I would like to ...
-3
votes
0
answers
15
views
Pad - Pad Clearance Proteus [closed]
A restlessness
As much as equibale: T6 Proteus
a picture Trace Style with his equivalencies a place in the Web where discharging
how he would be rule it of Diseño for 5A 30V
the Graphic 1 sign a ...
1
vote
2
answers
70
views
how to read power labels on home appliances?
I want to know how to read the power label of a home appliance in order to estimate energy cost.
I have provided a picture of an example power label
What i understand from the provided label is I use ...
- 13
0
votes
1
answer
59
views
Switch power to load using 2 GPIO pins, 5V and 12V
I will like to use 2 GPIOs on a raspberry pi to switch on a device (piezo buzzer), using 5V or 12V at a time.
My idea is to use two MOSFETs and place pullup resistors on the gates of the MOSFETs from ...
- 19
0
votes
0
answers
65
views
RC-circuit transient SPICE simulation diverges after adding one capacitance
I tried to build a lumped parameter RC circuit model for an induction machine. The SPICE simulation worked fine for a steady state with no capacitances. Then I tried to add capacitance one by one as ...
- 175
0
votes
2
answers
86
views
How does my AC adapter take 100-240V without a physical switch [closed]
I was checking if the AC adapter on my notebook could take both 110V/60Hz and 220V/50Hz (it can).
The AC adapter has no physical switch to select the input AC voltage. That got me thinking, how is ...
- 141
3
votes
2
answers
112
views
Why do VGA VSYNC and HSYNC need 47 ohm resistors in this schematic?
In Chapter 3 in this document there is a schematic showing a connection to VGA.
Why is there a 47 ohm resistor connected to VSYNC (GPIO17) and HSYNC (GPIO16)?
I managed to understand the other ...
- 179
1
vote
1
answer
44
views
Opamp current source - Impedance matching to a laser diode - MHz range current modulation
I want to modulate the current through a laser diode with the output of a (FPGA into R2R DAC)source. I am using an opamp to do voltage to current conversion as shown in the circuit diagram. The laser ...
- 23
-1
votes
1
answer
50
views
Would this situation I have work or would something blow? [closed]
I am constructing a robot that uses this chassis:
https://shop.pimoroni.com/products/dagu-wild-thumper-6wd-all-terrain-chassis?variant=39352843010131
It states that effectively It takes 7.2V and 6A ...
-1
votes
1
answer
28
views
How to test an MCCB for safe functionality?
Ive got a few MCCBs for an old system, what is a suitable way to test them to make sure that they function correctly and safely?
- 551
0
votes
5
answers
97
views
What's the difference between these two circuits? They both work
I'm a beginner. These two circuits are the same, except one has the resistors placed above and the other with the resistors placed below.
They both have the same current going through, except the ...
- 175
-1
votes
2
answers
47
views
What is the voltage range on ADC's inputs? Photodiode + TIA + ADC
Can someone here help me understand this circuit better? It's a photodiode -> transimpedance amplifier (TIA) -> ADC.
What is the voltage range on the ADC's inputs? AIN- and AIN+.
Which input is ...
- 11
-1
votes
1
answer
44
views
Transient Behaviour of current source into capacitor + resistor
Can someone please explain this transient behaviour circled - particularly the capacitor current?
Capacitor has a relationship of I = C * dv/dt.
I know the AC current will split based on the impedance ...
-1
votes
0
answers
32
views
How do I daisy chain multiple data streams? Is there a better solution? [closed]
I am doing a school project right now but am stuck on some hardware issues. I am struggling to create a way to daisy chain a bunch of sensors to connect to my Arduino Uno. I don't want to route back a ...
0
votes
2
answers
64
views
Synthesize of "REAL VARIABLES" in Vivado 2020.1
I am using the following libraries:
library ieee;
use ieee.std_logic_1164.all;
library ieee_proposed;
use ieee_proposed.fixed_pkg.all;
use ieee_proposed.fixed_float_types.all;
I cannot synthesize real ...
- 1
-2
votes
0
answers
26
views
How to measure change in TDS instead of absolute TDS through a TDS sensor?
I am using a total dissolved solids (TDS) sensor to measure TDS in an evolving solution system. The code below works fine to give the absolute TDS, but I would like to note the change in TDS over time....
- 105
0
votes
1
answer
78
views
Isolation for a long distance industrial CAN + audio box
I am working on an industrial control board + node network system. This system needs to be very robust, both for signal integrity as well as protection from transients.
The basic setup is shown here:
...
- 686
-1
votes
1
answer
34
views
Log potentiometer, rheostat, or something else for this 180 watt 2.1 PC speaker system? [closed]
I acquired an Acoustic Authority A-3780 2.1 PC speaker system with stand alone amplified subwoofer enclosure that you attach 2 satellites to.
Unfortunately, it was given to me without the mini-DIN ...
0
votes
1
answer
69
views
Connecting different ground together [closed]
I need your help on how to connect my ground together when designing my PCB. I have only one input with a ground (PGND) and one output with a ground (HGND). Both are high voltage and high current.
I ...
- 47
0
votes
0
answers
40
views
Software serial library for ESP32 S2 [closed]
I need help on software serial for ESP32 S2 in the Arduino IDE. I didn’t find any software serial code or library in google searching. There is a software serial library for the ESP32, it didn’t work ...
- 29
0
votes
1
answer
52
views
What happens on a DC-DC grid connection after a perturbation in the synchronous grid?
Consider the Continental Europe synchronous grid. This power system has some DC-DC connections with other countries (for example one with Great-Britain). Suppose now there is a sudden big outage ...
1
vote
1
answer
29
views
SMA connector pad size
I am designimg a board with an SMA connector for 8 GHz. The trace is calculated as a coplanar waveguide. For the given stackup, it is 0.25 mm wide. The SMA connector pin is also 0.25 mm wide.
If I ...
- 11
-1
votes
0
answers
51
views
Need proper no single-point failure bulb diagram
To solve vehicle bulb burnt and completely no light, I want to rebuilt vehicle bulb with no single-point failure design. Below is my diagram.
I put resistor just in case if one of the LED burnt, the ...
- 113
-4
votes
0
answers
27
views
Is this 5V-UPS circuit useful? [duplicate]
I have attached a picture of a circuit for my UPS:
My goal is to supply my Raspberry Pi a few seconds longer after power failure.
VCC = 24V, +5V = regular 5V supply voltage via LM2596. UPS =
5V ...
- 33
-1
votes
0
answers
36
views
Can I replace 74HC04 with 74HC2G04?
Can I replace 74HC04 with 74HC2G04 if I only need two channels? In the original design it's there to drive ignition IGBTs: https://secu-3.org/wordpress/wp-content/uploads/hwdoc/SECU3irev1/secu3i-BB-...
0
votes
0
answers
27
views
PIC18F power consumption
I am looking for a lower power PIC18F microcontroller that supports SLEEP mode (or even DEEP SLEEP mode without RAM retention). These power saving modes are widely advertised by microchip. They write ...
- 131
1
vote
1
answer
95
views
How to avoid square wave parasitic oscillation?
I try to recreate the circuit from here using discrete components logic gates. How can I avoid these parasitic oscillations in a square wave in one of its outputs?
-1
votes
1
answer
20
views
Altium Minimum Solder Mask Sliver error within thermal pad
I am designing a board with the DRV8837 IC, which has an 8-WSON package with a thermal pad and 2 vias. When running the DRC, I am getting the following error:
Minimum Solder Mask Sliver Constraint: (...
-4
votes
0
answers
76
views
information on microstrip antennas [closed]
to my fellow electrical engineers, I am a student in electrical engineering looking for references or textbooks in RF design. I found The Handbook of Antenna Design, how many volumes there? my guess ...
- 1
-1
votes
0
answers
50
views
What heat sink should I use for silicon rectifier that is replacing selenium rectifier in a TIG welder?
This is the new rectifier.
I could run some tests, I have no idea how much load would be a lot for this or what kind of cooling it would require.
Here's the wiring diagram:
Not sure what kind of ...
- 1
-1
votes
2
answers
53
views
Struggling with platinum wire/hotwire
I am trying to heat a thin platinum wire with a controllable power supply, using what I believe to be Joule heating. It doesn't have to get intensely hot, the main application is observing behavior of ...
4
votes
1
answer
311
views
What is DRAM Precharge?
I dont understand what is DRAM Precharge.
Is DRAM precharge used for reading the memory, is it applied before reading the row? or is it used closing the row access?
- 49
1
vote
2
answers
77
views
Are these MOSFETs the same? Do the two differences in the datasheet matter?
When trying to select parts the supplier has two P-channel MOSFETs listed. One an AO3401 and the other an AO3401A. The are only two differences between them. One in the general description. One ...
- 23
1
vote
1
answer
34
views
How do you know which pin corresponds Hall sensor 1, 2, and 3 so that I can pair it with the correct phase wire in a BLDC motor?
I recently bought a brushless sensored DC motor on Amazon which you can find here.
I didn't really know what I was doing at the time when I bought this motor, but now I'm realizing it might have been ...
- 149
-1
votes
0
answers
42
views
Cyclic Power Outage Explanation
A couple of evenings ago, I experienced a very unusual power outage. The power went out for a couple of seconds (perhaps three to five). The power then returned for roughly the same period. This ...
- 99
-1
votes
1
answer
123
views
Why don't inverters use BJTs to easily produce a pure sine wave?
This has been in my mind for a while now, I'm curious. Why not use a BJT H-bridge on the high voltage side, to convert the high voltage DC to AC. I saw a simple circuit that converts square waves to ...
- 126
1
vote
0
answers
55
views
What's the problem with this four-transistors XOR gate?
I aimed to design a XOR gate using as few transistors as possible. Eventually, I came up with this:
Designed and simulated here. The two terminals on the left are inputs, where the "low" ...
- 111
0
votes
1
answer
30
views
Controlling ADC (on/off) with microcontroller
I'm designing a PCB. I want to turn the ADS1120 ADC off/on using the SAMD21G microcontroller. The ADC has two power inputs, 3.3V analog and 3.3V digital. The 3.3V analog is connected to an LDO that ...
-2
votes
2
answers
69
views
Average voltage in PWM?
I have a doubt regarding average PWM voltage. Let's take a buck convertor with Vin=10V, Vout=5V. With this we can determine the duty cycle of PWM needs to be 50%. Thus means the MOSFET of the buck is ...
- 399
4
votes
0
answers
79
views
Can this Raspberry Pi UPS circuit work?
I created following UPS circuit to shutdown my Raspberry Pi 3A+ properly:
I would really appreciate if somebody can review my circuit. I know it's a little bit hard to read, but I'm sorry. I'm a ...
- 33
2
votes
1
answer
101
views
MOSFET being driven by an Arduino won't turn on without a 1M pulldown resistor
I'm driving an IRFZ44N MOSFET from an Arduino Uno (pin D2) via a 220R resistor.
On the drain, I have an LED with a protection resistor to +12V, and the source straight to ground. The Arduino is ...
- 21
0
votes
0
answers
49
views
Touching or moving LED circuit board causes PWM to flicker momentarily. Without touching the board there is no flicker
The circuit shown is set up as a constant current drive. It turns on and off just fine. When it's fully on the MOSFET on the low side of the LEDs is fully on and doesn't get hot at all and is not ...
4
votes
0
answers
97
views
Can chips be sensitive to mechanical stress after an electrical incident?
Is it possible to electrically damage a microcontroller (or any chip) in such a way that it becomes very sensitive to mechanical stress?
Some background:
We are developing a board with 7 identical ...
- 26.3k
2
votes
1
answer
94
views
How to achieve signal gating with trigger input
I am currently working on a project that generates enable pulses of extremely diverse lengths from microseconds to days and under normal operation will start execution under a trigger input.
However, ...
- 51
2
votes
1
answer
97
views
Problem with LED lamp PCB
Problems:
RED – PCB trace gets blown up.
PURPLE – There seems to be some arcing from the live terminal to the resistor on the side, which results in a bridging that blows the traces between.
So far ...
- 21