All Questions
187,908
questions
3
votes
1
answer
162
views
Modify lithium battery pack balancer
This is the lithium battery pack balancers available to me:
As Robojax has extensively explained in this video, this module is capable of balancing batteries with 67mA current (4.2v/62ohm) that is ...
- 247
-1
votes
4
answers
89
views
Why do we need variable (linear) voltage regulators when fixed regulators give the required voltages?
Digital ICs would need voltage rails 5.0V, 3.3V, 2.5V, 1.8V and 1.2V. There are fixed voltage regulators that can provide all of them. Where are the variable voltage regulators required and used then?
- 10.6k
0
votes
0
answers
18
views
How do I recharge an internal 18360 3.7 volt battery for a Cubii Pro Eliptical
I have a Cubii Pro exercise machine that uses a 3.7v internal #18650 battery for the bluetooth feature.The micro USB port broke away from the charging board and the manufacturer cannot supply a spare ...
- 1
0
votes
3
answers
28
views
Can you measure a powerbank's battery voltage at USB input connector?
I'm currently building a portable device, that is powered by a powerbank. I want to be able to measure the current battery "percentage" of the powerbank, with an esp32.
For this i thought ...
- 1
0
votes
0
answers
21
views
How can I controll the speed of a coreless motor with an RC receiver?
We used a brushed ESC 1A 5V (0.4g) DSM-ESC001 (unable to find its manual) for controlling a coreless 614 motor with 8mA no-load rating with an FS-X6B receiver. After checking some things out, the ESC ...
0
votes
2
answers
45
views
How to apply KVL with current source?
In order to write an ODE for the inductor current I have to write a KVL equation that includes the current source. How do I do that?
2
votes
1
answer
76
views
Monitoring the waveform of a low frequency squarewave, built into unit, with bnc output to scope
I want to monitor the waveform of a high voltage (8kV) 3Hz to 1000Hz DC pulse form. It has been suggested that I use 1pf capacitor in series with a 1000pf capacitor, then put the scope across the ...
0
votes
1
answer
25
views
Issues with I2C from MCP23017on Arduino
I am trying to use the MCP23017 expander chip with a Metro Mini by Adafruit (pinout below) and I can't get the microcontroller to connect reliably via I2C.
update
I connected the RESET pin to 5V and ...
- 161
0
votes
1
answer
25
views
Design Question about 64 SK6812 LEDs - Matrix vs 8x8 matrix
I am designing a 64 LED ring and am curious about the advantages of a matrix design for addressable LEDs.
For example, if I want to use 64 SK6812s, what is the difference between connecting all of ...
0
votes
0
answers
40
views
Need to identify component
I need to identify this component labeled TX08039 1119 on a pool pilot dig-220 power board 12042R2 in order to replace and repair chlorine generator for my pool, please. Pics of replacement board
- 1
1
vote
1
answer
34
views
Seeking clarification on equation used in MIPS assembly problem
I'm currently studying MIPS assembly code, and I'm having trouble understanding the solution for question (b) of a particular problem. I was hoping someone could help me clarify a specific part of the ...
- 11
1
vote
3
answers
38
views
7 segment display malfunctioning with ATmega8A
I am using an ATmega8A and want to take 8-bit input and display the corresponding binary in decimal form on three 7-segment displays but when I do it some unwanted segments light up dimly. What can be ...
-1
votes
1
answer
48
views
How to make no flash 4 bit ADC converter [closed]
I'm trying to make 4 bit ADC converter, but all I can find is a 4 bit flash ADC converter like on the picture below
but I need no flash
- 71
0
votes
1
answer
85
views
What is the conventional direction of voltage in this circuit?
The problem circuit is like this:
If the diode is conducting, we can replace it with a linear circuit of a generator V_d, and an internal resistance r. Which component comes first after replacing the ...
- 25
0
votes
1
answer
92
views
How does upgrading car brake lights to LED turn on the ABS warning? Is it a feature or bug? Other solutions than LED load resistor? [closed]
It's a well-known issue that when changing from bulbs to LED, a warning light will come on like the ABS light, but some had other completely brake-unrelated problems.
In my car there is no ABS warning ...
0
votes
0
answers
31
views
Implementing FSM with Sequential Logic
I am trying to complete Problem 4 of this MIT Computation Structures lab, which requires you to use a circuit simulator called Jade to build a sequential logic circuit that implements the below FSM:
...
- 25
1
vote
1
answer
27
views
Nodal analysis with current dependent voltage source
V2= 4Ix + V1 (1)
V1 Node
V1/6 + V1-V3/12 + V2/2 + V2-V3/3 =0 (2)
V3 Node
1 + V2-V3/3 + V1-V3/12 = 0 (3)
I can get this three equation by text book, but I can't understand equation (1). Can anyone ...
- 25
0
votes
0
answers
21
views
XL6009 voltage booster damaging Arduino Uno from Vin pin
I used two Li-ion batteries (3.7 volts, 1300 mAh) connected in parallel, charged by a solar panel, connected to a charging module (TP4056) and attached the load of TP4056 to the voltage booster module ...
0
votes
1
answer
61
views
What components can be used as an alternative to vibration motors?
I am building a project that will vibrate at certain times. The item being vibrated is 300-700 grams (still working out the material). It needs to be a noticable vibration (like a phone vibration), ...
0
votes
0
answers
29
views
Is this PSU configuration correct for dual power rails and a virtual ground?
I am pretty new to electronics, and I am just not understanding if I have the right configuration on my Tektronix PS2502g PSU. I am trying to supply voltage to a LM741 op-amp but do not appear to be ...
- 101
0
votes
1
answer
65
views
Identify this blown up IC?
Marking is IOR209M.
But I cannot find any datasheet.
My best guess is a SOP8/SOIC8 MOSFET.
- 247
1
vote
1
answer
37
views
Nodal Analysis Q
Hello, I'm studying Electrical Engineering, but I'm confused about nodal analysis. How to find all nodal voltages and the current through the 4 Ω resistore?Please someone help me to understand this ...
- 25
0
votes
0
answers
25
views
Tilt Compass calibration using matrix multiplication: How to derive the soft iron 3 by 3 correction / calibration matrix values?
Magnetometers are useful but normally suffer from offset and magnitude errors. The offset (or hard iron) errors are corrected by adding half of the maximum minus the minimum readings for any given ...
- 3,200
0
votes
1
answer
50
views
Cable size for 400 W solar PV, 7 m long run
I have 2 Renergy 19.2 V 200 W panels, the rated current for each is 35 A. I intend to wire them in series, and the cable run to the grid tie inverter is 7 m in length. Looking up on the Internet it ...
- 103
0
votes
2
answers
79
views
When is the diode conducting in this circuit?
Can someone tell me when is the diode conducting and when it isn't? I did calculate the voltage between its electrodes, so I disconnected the diode, then for some unknown reason I turned the current ...
- 25
-1
votes
0
answers
47
views
Trouble with Laser Light Alarm System
My alarm system circuit comprises of:
BC-547 transistor
2.2 kΩ resistor
An LDR
3.7 V lithium-ion battery connected with a switch
LED light
Buzzer
Laser light
The resistor is attached to the collector ...
- 1
3
votes
1
answer
210
views
Is it possible to design a compact antenna for detecting the presence of 50 Hz mains voltage at very short range?
I have a mains cable buried in the wall. I would like to permanently place a small battery powered device on the wall over the cable's location and have the device be able to detect if the cable is ...
- 311
1
vote
1
answer
63
views
Wireless power transfer
we try to make wireless charging system. We set up the circuit on breadboard but the voltage across the coil is zero. Why?
1
vote
0
answers
13
views
SST12LP15B: What is the purpose of the length/width specification for connecting pin 12 (VCC3) to VCC?
In the datasheet for the SST12LP15B, figure 11 shows that pin 12 (VCC3 - power supply, third stage) is connected to VCC via a "Length = 220 mil,
Width = 10 mil" trace. Why is this required? ...
0
votes
1
answer
22
views
Cyclone III FPGA 16x2 LCD repeat one character instead of displaying complete word
So I am trying to use the LCD on the cyclone III FPGA.
I have written this verilog code that should display numbers 0 to 9 then letters A to G
Compiling the code has no errors at all
However, when ...
0
votes
1
answer
53
views
Negative feedback in an opamp
I am a fresher and have been introduced to a basic electronics course at college.
Recently our professor was introducing us to opamps and was referring to negative feedback as a rectification to any ...
- 81
1
vote
1
answer
64
views
How is a "smart pull-down" implemented
Some devices have a smart pull-down resistor. It is active until the user drives the pin, and as soon as a threshold is reached, the pull-down is deactivated.
How is this implemented, e.g. if I wanted ...
- 11
0
votes
3
answers
66
views
Voltage doubler circuit working
I understand that when the voltage at the anode of the first diode is greater than the cathode it turns on, however immediately after the first two positive cycles, how does the diode turn on?
It ...
0
votes
0
answers
44
views
Pactical component search for building a circuit [closed]
I am trying to implement the circuit shown below, taken from this article.
I have never done such a thing, I have only done spice simulations.
The circuit functions at 10GHz.
There is a companny which ...
- 159
-4
votes
0
answers
33
views
Memory Module Design [closed]
It is desired to have memory of 1GByte given that a 18-bit address bus is used to address memory location. Design the decoding architecture in order to access complete 1GByte memory also calculates ...
0
votes
0
answers
19
views
Is there any provided footprint for the AS5F18G04SND-10LIN from Alliance Memory?
Documentation link
All I could find in the documentation was a really low resolution (and impossible to read) package outline. I also looked elsewhere for a footprint for that package and the IC ...
- 43
2
votes
2
answers
413
views
How can I manually analyse this simple BJT circuit?
I can calculate Ve and Ie, assuming that Ve = Vb - 0.7 = 14.3 V.
Ie = (14.3 - (-20))/10000 = 3.43 mA.
How can I manually find Vc, Ic and Ib?
0
votes
0
answers
59
views
How should I wire a passive audio splitter for studio monitors?
I am building a passive audio splitter that takes in two balanced mono signals (on TRS) from an audio interface and then it should be able to switch the routing of the signal using a DPDT switch.
I ...
0
votes
0
answers
31
views
4-Bit Barrel-Shifter with 4x1 Multiplexers
I have a question regarding an exercise I have to do. I am supposed to build a 4-bit barrel-shifter using 4x1-multiplexers. I have 4 inputs and 4 outputs. The position shift should be n=(2*B)+A. I ...
- 1
0
votes
2
answers
36
views
What is the value of GPIO input along a rising or falling edge?
I'm using the gpio_get_level function documented here, which states that it returns a 0 or 1 depending on the value. What is the value if this function is called ...
- 343
2
votes
2
answers
445
views
How do Spectre patches work?
How could Intel/Microsoft provide software patches to Spectre, which exploits the speculative execution nature of superscalar processors, which is a hardware feature that cannot be modified or ...
0
votes
1
answer
35
views
Water flow sensor stays on until tapped
I'm using a hall effect rotor sensor to control power to a UV purifier connected to the outflow from a reverse osmosis undersink tank system, connected to the inflow of the UV purifier chamber.
(https:...
0
votes
0
answers
30
views
Connection of piezoelectric sensors for more output voltage and stable voltage
What connection of piezoelectric sensor is more suitable to connect six piezoelectric sensors? Is it in series, parallel, or series-parallel? Is there any specific calculation formula that can be used?...
2
votes
0
answers
33
views
Overvoltage Clamping protection for Boost Converter
I think my circuit is failing because of ESD and/or transients when initially connecting my device to a supply. How should I go about protecting the gate of M1? What's the best way to clamp the ...
-2
votes
0
answers
17
views
Trying to identify this component on a Logitech remote. Above it is marked r398 r400 c173 with a arrow pointing down right next to that it is r87 c195 [closed]
I have a Logitech universal remote touch screen. I believe it is the 1100 model it does not power on or charge but the light flickers and blinks on the screen and lights up for a second then cuts back ...
1
vote
1
answer
62
views
Can I use an SDR to transmit on the ISM band without a license?
I would like to use my SDR to transmit arbitrary data.
Can I freely transmit in the ISM bands without any license, as long as I abide by the regulations? My understanding is that I can transmit at up ...
- 113
0
votes
1
answer
28
views
S-Parameters Re-normalization
When we talk about S parameters for a certain number of ports we typically reference each port to a specific impedance, most of the time to one common \$Z_0\$ impedance, but in general terms to a ...
- 439
0
votes
2
answers
49
views
Why is does my INA121 instrumentation amplifier not amplify my load cell's signal at high loads?
I am applying a high load (150-200lbf) to a (mV Wheatstone bridge) load cell rated for 200lbf (link to datasheets at bottom), and amplifying the differential signal with the INA121 instrumentation ...
- 1
1
vote
0
answers
15
views
Online motor inductance measurement at different rotor angle
I wanted to measure the inductance of PMSM at different rotor angles. I'm familiar with the offline methods of measuring motor inductance but would like to measure a motor's inductance while it's ...
1
vote
1
answer
60
views
FPGA Output to another FPGA Input, 3 meters away
I have one FPGA (Artix-7 XC7A100T-2CSG324C) and it's connected by a PCB trace to another FPGA (Artix-7 XC7A100T-2CSG324C). The PCB trace has these characteristics, 3.4 meters long, 0.154mm width, 0....
- 13