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H: Why did they use ultrafast diodes in a 50 or 60 Hz bridge?
This is again from an HP power supply (PSU). The incoming 230 V is rectified into 340 VDC and is fed to a switched-mode supply. The odd thing here is that the manual for that unit, HP6023A, has different diodes for CR1, CR3, and CR2, CR4.
CR1 and CR3 are l... |
H: Problem with state machine that calculates the Greatest Common Divisor in VHDL
I am supposed to implement the greatest common divisor in VHDL. The testbench and the interface were provided. However, every time I run the simulation, this thing gets stuck in state 6 (q6) and I have no idea why.
When I look at the ou... |
H: RS485 Eye diagram - does it look good?
I got a new diff probe, I am trying it out on RS485. I'm triggering on the rising edge. The RS485 is running at 25Mhz.
Does the eye diagram look good?
Could I double the speed (50MHz) and be ok? (do I need to worry about overshoot?)
What should one look for in an eye diagram... |
H: Why a source which has high source impedance modeled in general as current source?
Is there a practical example by using a circuit where a source better modelled as a current source if it has a high output impedance? I have been hesitating to ask here but couldnt figure out myself. Im trying to grasp the logic behi... |
H: What is this "drive circuit" for CCD sensor referenced to?
I had a look at the TCD1304DG CCD sensor which I consider using in a project. The datasheet is pretty lucid, but I couldn't figure out what the following diagram is supposed to say:
Is this just a common way of illustrating an analog signal?
AI: It means ... |
H: How to know how many phases a BLDC has?
I have a quick question, how do I know how many phases a BLDC has? For example, an E-bike motor kit has three motor wires: yellow, green and blue. It also has three wires for the hall effect sensors: yellow, green and blue plus two more wires for powering up the sensors: blac... |
H: Powering high-power laptop from DC without inverter
Context: We live full-time in an RV (a travel trailer) while traveling around the US. We have 300Ah of 12V Lithium batteries, a 3,000W inverter and 600W of solar. Although we have an inverter, it has a parasitic draw of ~35W (~3A). We camp off-grid ~90% of the tim... |
H: What is this radio signal coming from my phone?
I've built myself a crude EMI probe:
I then pointed it at the top part of my phone when the phone was powered on, and I saw the following waveforms on my scope.
First off, there are spikes every 525ms:
These spikes consist of exactly 6ms of some kind of waveform:
Z... |
H: Unknown model type bjt - ignored
I am trying to use Transistor model as in the NGSpice manual 8.2 BJT Models (NPN/PNP):
.model QMOD1 BJT level=2
however, I got this error:
q1 n15 n16 n17 qmod1
could not find a valid modelname
Warning: Model issue on line 61 :
.model qmod1 bjt level=2.end ...
Unknown model type... |
H: Are there Multi-Turn Absolute Encoders that Store the Number of Turns in Non-Volatile Manner?
I have been learning about absolute encoders, and am testing a multi-turn absolute encoder (link to datasheet is here). During testing, I realized that after shutting down the power, although the encoder position is saved,... |
H: How to add custom ROM chip to Proteus?
I’m new to Proteus and deciding wether to use it for my current project.
There are a few EPROM chips in my design that do not exist in the Proteus library:
M27C1024 (64Kx16)
M27C322 (2Mx16)
Is it possible to add them to the Proteus library with support for simulation?
Or is ... |
H: 555 Timer - How to quickly discharge RC capacitor
I'm using a 555 timer to turn off an LED with delay.
Here is the circuit.
All I want to implement is, to get the input voltage changes in output with a constant delay.
When I close the switch, the capacitor in RC network being charged and the OUTPUT will be LOW aft... |
H: Doubt on PSRR calculation and result
I designed the following circuit in Cadence Virtuoso:
It is a two stages op-amp with a compensation network (resistor and capacitor). VDD=1.8 V, VCM=900 mV, VB2=1.28 V.
The DC gain is 73 dB.
1st question: I have to calculate the PSRR (power supply rejection ratio). The book on... |
H: Heatsink on top of SMD plastic IC or bottom of PCB?
I often do designing power modules and always wonder if there is some kind of rule how to properly cool SMD devices.
I always look at final products from other companies and some are placing heatsink on bottom of PCB, while others pleace them on top - directly on ... |
H: CDMA basic working principle
I find it hard to find on the internet a simplified explanation of the principle of operation of the CDMA system. Could you give me an example of how it works and how a receiver can correctly identify a user's message?
Precisely, as I understand it, each user sends a certain message, of... |
H: Characteristic Impedance without transmission lines
let's consider this three port power divider:
I saw somewhere that the reflection coefficient Г11 can be calculated with the formula Г11 = (Zin - Z0)/(Zin + Z0), where Z0 = 50 Ohm.
Now my questions are:
1) What is Z0? There are no transmission lines here. I thoug... |
H: Unknown "D" variable on datasheet's max pulse current description
I was reading the datasheet for an SFH4545 IR LED. In the "maximum ratings" category, the "surge current" value's conditions are: $$t_p=100\mu\text{s},\,D=0$$
What does the D mean? At first, I thought it could be the duty cycle, but it'd be strange i... |
H: How is the boolean expression for mux2 and mux4 deduced?
I've been looking at the following article: https://www.electronics-tutorials.ws/combination/comb_2.html
I am confused as to how the boolean expression Q = a'b'A + ab'B + a'bC + abD is deduced for mux4, and what it would be for mux2. How is it done with kmaps... |
H: How to use MATLAB to observe the effect of multiple damping factors?
I want to use MATLAB to observe the effect of changing zeta (damping factor) on system response?
Here is a m-file code that plots three responses: underdamped, overdamped and critically damped.
clc
clear all
close all
num1=[16]
den1=[1 4 16]
num2=... |
H: Missing contamination delay specification for a component
If IIUC: contamination delay (\$t_{cd}\$) is the time where the signal level on the output of a component starts to change in response to a change on the component's input, while the propagation delay (\$t_{pd}\$) is where this signal level change on the out... |
H: door bell detector using NodeMCU
i modified my door bell with a NodeMCU which is now capable of triggering the door opener using a relay. Now I want to add a door bell detection to this system. I figured out two contacts which supply a DC of ~5V for a second while the bell rings.
How can I connect this to the NodeM... |
H: Driving a MOSFET gate with an NPN BJT
simulate this circuit – Schematic created using CircuitLab
Today I saw an LED dimmer product. The driving circuit was like in the schematic. It was a cheap one but the circuit looks inefficient to me. When the BJT is not conducting, R1 pulls the gate high and the MOSFET starts... |
H: Output of LM393 won't swing LOW unless it is pulled up with a LED
I built the following circuit using an LM393 as part of a noise gate for audio applications. It's a voltage comparator with hysteresis.
I originally connected a 10 kΩ pull-up resistor and then added a 5 mm UV LED to serve as a visual reference. The c... |
H: Boost Converter - Input follows Output
I have a boost converter.
\$V_{in}\$ = 7V
\$V_{out}\$ = 14V
\$I_{load}\$ = 0.35A
While testing, I observe that as long as Vin<14V, I observed switching at the inductor switch node.
But, as I increase my input voltage, Vin>14V, I dont observe the switching at the switch node. ... |
H: How to bypass on/off momentary switch?
I have a Bluetooth receiver and was wondering if there was a way to have it turn on when power is plugged in without having to press the on switch? the middle button is the on/off switch.
AI: If the unit works the way you require by holding the power button as you power up the... |
H: If a 4-bit binary digit in 2's Complement form is stored in 8 bits how is it represented?
I am quite new to Digital Logic. I got this doubt while solving a problem.
If a 4 bit binary digit in 2's complement e.g. X3 X2 X1 X0 is stored in an 8 bit space what will be the representation in those 8 bits.
As far as i kno... |
H: How to use reed switch to change operating modes?
I have a circuit of LEDs - say L1-L10. My requirements:
No visible switch
Illuminate the LEDs successively (only ever one at a time) every time the user passes a magnetic "wand" over the switch. (Mode 1-10)
Using the same "wand" permit the user to set the circuit... |
H: High - Frequency Carrier Necessity
let's consider a basic scheme of a receiver.
Now I have two questions:
I was told that the presence of the mixer is important since it is useful to delete the carrier frequency of the received signal. In fact, it is very difficult to work (i.e. amplify, filter etc) with high fre... |
H: Is there software for converting a picture of a board into an schematic?
I need to reverse-engineer several simple single-sided boards. I have very good quality pictures of them so I was thinking that maybe there is software capable of getting the schematic from the pictures (up & down) or at least an approximation... |
H: Why is the transfer function of this non-inverting low-pass filter wrong?
I came across this block in a larger circuit:
With a transfer function (in pole-zero form) of;
$$
H(s) = \frac{s+30000}{s+5000}
$$
which was found using KCL on the inverting terminal of the op-amp.
As I am not used to finding transfer func... |
H: HX711 adc read functions gives different accuracy
I'm reading data from HX711 with stm32F1 but accuracy of the data are awful. when i read data with arduino the data ten times good if we compare with stm32 results. these are my read functions.
Arduino function:
long HX711::read() {
// Wait for the chip to become... |
H: Meaning of HCLK, FCLK, DCLK, PCLK
Can somebody please clarify the meaning of these acronyms in the context of ARM Cortex:
HCLK
FCLK
DCLK
PCLK
I think HCLK means half clock? I know that PCLK is related to APB, so maybe it means peripheral clock? I am clueless about the other two.
AI: There is no universal meaning ... |
H: Computer Power supply not powering when connecting power pin to the ground
I have an old power supply which hasn't a power button to turn on/off.It is made by Enlight corporation.The model is: ATX-1123B 230W.
I found an image with the ATX power supply pinouts.Here it is:
As you can see, the green pin(PS_ON#) is fo... |
H: Cleaning with less than pure IPA (isopropyl alcohol)
I want to clean a SO-DIMM memory that was contaminated with bottled drinking water. This was not "mineral water" intended for drinking. It was the high volume bottled drinking water from one of the world's largest "soda" companies. This device stopped working aft... |
H: Protection against a circuit being closed too long or failing closed
I'm prototyping a device that allows me to electronically open my front door, which it accomplishes by using a relay to close an existing circuit in my house. All I know about this circuit is that it measures around 12V AC.
Now, I'm far from keepi... |
H: Lattice — Should I prefer IPX/PMI over Verilog arithmetic builtins?
Like any FPGA vendor, Lattice provides a number of IP modules for users to put in their designs. I tend to use them whenever possible, but sometimes I doubt if they have any substantial benefit over plain Verilog.
For example, I can create a simple... |
H: What is the use of two n mosfets with their sources tied together?
The circuit I'm looking at recommends two n-channel mosfets in series with their sources tied together between it's output and the power input.
pin description:
High voltage open-drain gate driver, which may be used to drive an NMOS/PMOS power swi... |
H: How to interpret data sheet for an RF 50 Ohm terminator, is it 2 Watt or is it 0.1 Watt
I am trying to find a suitable RF 50 Ohm terminator for my application. I think the following will work:
http://www.amphenolrf.com/media/downloads/7034/132360.pdf
I am a little uncertain though as it states in the "Electrical" ... |
H: Is negative resistance possible?
I was reading Hayt Kemmerly Engineering Circuit Analysis Book,(I tried others, but this is the most comprehensible to me.), And I came across this circuit. I understand the first two, but I don't understand how, in the 3rd circuit (c), there is negative voltage through the resistor ... |
H: Does placing additional capacitors in parallel with CJ7805 affect its performance?
I'm not sure if this is a stupid question, but I'd still prefer to ask than regret it later. I'm designing a PCB with the CJ7805 which, like the LM7805, can supply a steady 5 volts. In this case, it's to power a Teensy 3.6. There's a... |
H: MOSFET as a Capacitor in IC
I was reading in a book that it is often possible to realize a certain capacitance in Integrated Circuits by exploiting the Gate Capacitance of a MOSFET. I read that the main disadvantage of this technique is the presence of a resistance between drain and source, which determines some lo... |
H: External Dupont male connector
I would like to program my board without opening the enclosure.
On the PCB I have a standard 2x3 Dupont male connector that I use with the Atmel ICE programmer. I am looking for a similar connector to be mounted externally but I did not find anything useful. Do such connector exist or... |
H: What is purpose of the "assignments" in the Qsys custom component editor signals and interfaces tab?
Here is the image showing what I am talking about,
For Avalon Memory Mapped Slave port I can see that there are 4 options already there and they are already assigned custom values.
I just want to know, what is the ... |
H: 1 TTL IC -> inverter + 2-input NAND + 3-input NAND
I came across this question in my homework:
Implement the following gates using only one TTL IC: one inverter, one 2-input NAND and one 3-input NAND.
The type of IC they're talking about has 14 pins, where pins 7 and 14 are GND and Vcc respectively. Also, the res... |
H: What kind of connection to use between two circuit boards that move with respect to each other?
I need to connect two circuit boards - one with a microcontroller, power circuitry, display, etc to another with several sensors on. The connection will require somewhere between 4-10 lines - 5V power, ground, I2C data a... |
H: How to use output PWM in AVR
I have this code to blink an array (8-led) of led one after one:
#include <avr/io.h>
#include <avr/delay.h>
#define dela 500
int main (void)
{
DDRC = 0xFF;
for(int i=0; ; i++,i%=8)
{
PORTC |=(1<<i);
delay_ms(dela);
PORTC &= ~(1 << i);
delay_... |
H: SAR ADC DAC Question
Hi,
This is an extract from MT-021 from Analog Devices about SAR ADCs. In particular, it shows a circuit in which the Track(Sample) and Hold block of the SAR architecture AND the DAC of the SAR architecture are implemented as one.
My question is : The description/circuit is explaining about t... |
H: Resistive braking of series wound DC motor
I am looking at braking a series wound DC motor by putting a resistor across the motor feed terminals.
All of the sources that I have looked at state that the polarity of the field winding needs to be switched as you start braking. I understand how this works and how it ap... |
H: Can someone identify this old round connector?
I am trying to develop something to control an old antenna rotator, and it has a connector like this one:
It does not seem to be a simple audio connector, but is more or less of the same size. What it its name? Is it possible to find a male connector for it nowadays?
... |
H: CMOS Flash vs SD: Can I put a Gamecube Memory Card in an SD reader?
Backstory
I've decided to run "Homebrew" on my Gamecube (and writing Homebrew for n00bs to document the process).
Unfortunately, it seems that there's no way to do this without buying special hardware. Specifically it seems that you have to have at... |
H: Conductivity of liquids (3D resistor network)
Hi I'm an electrical engineer but have not seen this problem before. I'mn trying to measure/calculate the resistance of a liquid.
Background:
I'm working on an electronic device that can come in contact with a liquid. Unintentional, can be avoided but is not considered... |
H: STM32 ADC and timer(s): Measuring moving average peak voltage of PWM signal with varying amplitude
I want to measure a moving average of the amplitude of a fix frequency, fixed dutycyle PWM signal with slowly varying amplitude but in a noisy environment (DC motors).
I want to use as little as possible CPU power to ... |
H: Submersible electronics
I'm currently working on a hobby project that uses a MS5540C.
It will basically measure the water depth and temperature.
My general thinking was to encapsulate the whole thing (except the sensor) in wax to make it water proof.
Could I use epoxy instead? What general consensus?
added:
The sen... |
H: TUHS3F05 without other components
I'm planning to use TUHS3F05 for my ESP32 project. I'm very space limited so I need to optimize place as much as possible.
In datasheet it is recommended that TUHS* it should be used with other components yet in my testing it worked great without them (I was testing for over 10 day... |
H: What is meant by taking dual of a boolean expression?
I read online that if we have a set of SOP terms giving a boolean expression, then the POS terms of the complement of the SOP terms will give the same expression.
POS(f)=SOP(f').
This is called taking the dual of the expression. How does this work?
If I have:
f ... |
H: Can I power a MOSFET from my uC in this way?
The uC is a PIC10F220, which if I read the datasheet correctly can supply 25mA absolute maximum on its pins. The MOSFET that drives the load is actually 4 pcs NCE0140KA in parallell, but drawn as one for simplicity. The combined capacitance of the MOSFET's is 13.6 nF. I... |
H: How do I efficiently search for ICs?
I am a computer engineering student with an electronics background (i.e. mandatory circuit design and analog electronic courses) and my degree thesis requires me to design an electronics project.
So now I have this project to get done and of course I have to look for ICs that d... |
H: What (if anything) are the standards for "generic" part numbers?
If I buy an MMBT4401 from Diodes, Inc., I get a 40V, 0.6A NPN transistor in a SOT-23 package. If I buy an MMBT4401 from ON semiconductor, I get a 40V, 0.6A NPN transistor in a SOT-23 package. If I buy an MMBT4401 from Micro Commercial Co,... you get t... |
H: What does this diamond, arrow and tail symbol means in schematic diagram
What does these symbols in the electric schematic means? I believe the arrow head indicates the direction of flow of current from left device to right device. What is the tail of that arrow symbol is? Is that source of current? What does t... |
H: LTspice table function
How does the table function work in LTspice?
In the LTspice library, it says,
table(x,a,b,c,d,...):
Interpolate a value for x based on a look-up table given as a set of pairs of points.
I don't really understand what it means. Could somebody help me understand what it does?
Example:
.step par... |
H: Transfer function for Sallen-Key Low-pass Filter
How can I find the transfer function H(s) of the following circuit by using the nodal analysis?
My thoughts woulb be:
the equation for the node
\$ i_1 = i_1 + i_3 \$
\$ i_1 = \frac{U_e - U_1}{R_1} \$
\$ i_2 = \frac{U_1-U_2}{X_{c1}}\$
\$ i_3 = \frac{U_1 - U_a}{X_{c... |
H: Converting single-phase to three-phase for City & Guilds 2391 practical
For my City and Guilds 2391 course, I will be testing a three-phase distribution board with a motor and single-phase sub-main.
I am finding it hard to memorize the test procedures. So for me it's about repetition, but naturally I don't have a ... |
H: How does ohm's law for capacitors affect this scenario?
Ohm's law for capacitors is i = C dv/dt
simulate this circuit – Schematic created using CircuitLab
Clearly there's a zero change in voltage across C1 always, but since C1 is a capacitor, it can hold charge and the current is not zero.
AI: The fact of the matt... |
H: How is powering an LED with a 9 volt battery possible without burning the LED?
I used a 220 ohm resistor with a 9V battery and the LED works fine. However, most sources say the forward voltage in a red LED is typically only ~2 volts. Going by this logic, the LED should have burned out, as resistors only limit curre... |
H: Identify component in 1970s vintage video game from photo
Can anyone identify these two components, marked "SKY 4433" and "2.000000 K.D.S", respecitvely? Are they capacitors, crystals, or something else?
They are from a vintage 1970s ball-and-paddle-style video game (Parat Game by Technigraph) based around the AY-3... |
H: Pitch of FPC connector
I need to interface a display which has an FPC connector. I'm a bit confused as to what is the pin pitch. The datasheet's drawing is a bit confusing because the dimension lines are a bit off-centered with regards to the pin's midpoint. If someone could help me out, that'd be great.
Datasheet... |
H: GND arriving to the wrong pin of this chip on my PCB
I had originally done a PCB for another chip. All pins I'm using (1, 2, 3, 17, 18, 19, 20) are fortunately correct for the ATtiny4313 I'm now using, except GND that arrives on pin #4 of my PCB ... instead of pin #10!
An option for my prototype PCB (I don't want ... |
H: Purpose of an Electronic Speed Controller(ESC)
I need to implement a brushless dc motor and I know the motor needs to need constant control to ensure that consistent torque is applied to the rotor.
What control does the ESC provide and what control is up to the engineer?
(I will be using scalar control) My understa... |
H: Memory Boundaries in SRAM
I am trying to use the GPDMA which is present in LPC43XX parts.
The UM10503 data sheet constantly warns about memory boundaries (datasheet section 21): basically it says that you don't want to try a burst across a memory boundary otherwise "the transfer will be split into two AHB transacti... |
H: How to calculate a lithium-ion battery's discharge time at a specific load?
How do i calculate the discharge time for an lithium-ion battery at a specific load?
Let's say i have a lithium-ion battery with a nominal voltage of 3.7 V, a cut off voltage of 3.0 V and a nominal capacity of 450 mAH. The battery is discha... |
H: Accurate signal reconstruction
While reading through this page I came across following info:
"For accurate reconstruction using sin (x)/x interpolation, your oscilloscope should have a sample rate at least 2.5 times the highest frequency component of your signal. Using linear interpolation, the sample rate should b... |
H: Excitation of a resonant cavity
let's consider this picture in which a cylindrical resonant cavity is excited through a waveguide.
I have some questions:
1) Why is it called "Magnetic Coupling"? I thought this excitation simply was the propagation (through the slot) of the wave already present in the waveguide tow... |
H: Mismatch on string of resistors for DC bus voltage sensing
In the picture below, you can see a string of 10 resistors used for DC bus voltage sensing. I think that the blue resistors (the original ones) are 400k/1W. The colors are: yellow, black, black, orange. One of the resistors got open, and I replaced it with ... |
H: How to interpret the FFT of the mains voltage in this case?
I coupled the 230Vrms AC mains voltage to a scope channel through a 10Vpk-pk step-down transformer. I can imagine the transformer will already filter high freq. noise but I thought I can still see some spectrum for at least narrower bandwidth. So then I sa... |
H: How to calculate the voltage across Va and Vb?
Attached is the circuit I have been analyzing.
Here the intention is to calculate the voltage across V_A and V_B - (See the red colored letters in the circuit diagram.)
I have calculated V_R1 using Kirchhoff's voltage law as follows,
Edit
I have taken voltage across ... |
H: Is there a more efficient alternative to pull down resistors?
I am building a LED spinner circuit and I am at the point of optimizing it. The whole circuit itself only draws about 10-20mA max. I was today looking at this part of the circuit:
Now as you can see, when my switch is at position 5, it turns the circuit... |
H: How to connect CPU with RGMII pins to an LTE module that takes only SGMII signals?
The Hi3519 Hisilicon CPU has RGMII pins. We are trying to connect it to the EC21 LTE Module from Quectel which contains SGMII pins. Would using two Realtek RTL8201F-VB-GG PHY chips with magnetics between them work as shown below?
EC2... |
H: Determining when a serial connection is opened
I have a PIC24FJ MCU with an FT232RL USB to UART controller. My design has end users opening a serial connection to my MCU to set parameters and get debug information.
My question is: How can I tell when the end user has opened screen/PuTTY/etc to my device's COM port?... |
H: Why is the initial current in this capacitor not continuous?
I am working on this circuit:
Basically, \$V_1\$ is on all the time, and \$V_2\$ turns on at \$t=0\$. For the conditions at \$t=0^-\$ (the time just before zero), I can see why the voltage across the capacitor is equal to \$V_1\$. The current through the... |
H: How to control contactors with sequenced time delays
Updated schematic to correctly reflect what I wrote below...
I’ve had to add more functionality:
Top left: The linear regulator has been replaced by a LM2575-5. This will be the HV variant with a Vmax of 60v. The Diode is a Shottky, not a Zener as shown.
Botto... |
H: Transmission Line Mismatch Simulation
I found an interesting simulator for transmission Lines. I can set a precise value for the load and then see what happens. For instance, let's suppose Z0 = 50 Ohm and let's consider these cases:
1) (almost) Open Line (the simulator allows at max 10000 Ohm for a load)
In this c... |
H: PCB strip from manufacturer
When we manufacture certain PCBs, where 50ohms impedance matching is required the manufacturer provides a small PCB strip along with the actual PCB. What is the actual purpose of this?
AI: To verify that the matched impedance is in fact 50 ohms.
You can use a network analyzer or Time do... |
H: How is the Collector-Base region reverse biased in Common Collector configuration of BJT?
This is the circuit diagram of an n-p-n BJT in Common Collector configuration, taken from the book :-
I know that for the transistor to operate in active mode :-
the Emitter-Base junction should be forward biased.
the Colle... |
H: Does a robotic lawn mower sense that it is outside the perimeter wire? If so, how?
I have a robotic lawn mower. Sometimes if the grass is really slippery, the lawn mower can slide outside of the perimeter wire. When that happens, the lawn mower shuts down and I get a notification on my phone. The notification says ... |
H: What does Ch-Ch isolation stand for regarding this context?
This scope specs mention the following inputs:
I don't understand what meant by channel to channel isolation here. I made a continuity test and the input grounds of two channels are connected. I thought Ch-Ch isolation meant the input channels' grounds ar... |
H: Beginner - Why do voltage/current behave this way
I was checking falstad and came around this resistor circuit which lost me completely :
Knowing that input voltage is 5v and current is 17mA :
1- Why is the voltage 0 after the 200Ohm resistor knowing that It's 3.4V before It ?
2- Why is the current flowing without... |
H: Can two Radar motion sensor, running next to each other, result a false detection?
I have two CDM324 Radar motion sensors.
I want to run the two sensors close to each other.
The transmitted frequency is roughly 24 GHz and I am afraid that a small shift in one sensor transmitted frequency could enter the received p... |
H: How to decipher capacitor markings
yet another noob here. answer is probably obvious for most but not for me really. Just wondering how to interpret markings on these capacitors (red circles)
ps. first lesson learnt :)
AI: Take a clue from the black silkscreen painted on the printed circuit board surface:
C... |
H: Flash in MCCB when switched off
Recently I switched off several molded case circuit breaker (MCCB) and saw a flash at the back of the breaker for an instant. This happened to all the MCCB on-site (around 14). The MCCB are all rated correctly - 200A capacity with a feed in peak load of 145A.
Is this perfectly normal... |
H: Fourier Coefficients
I have no idea how to solve the following exercise, can you help me, please?
Find the periodic function whose Fourier coefficients are
$$C_{k} = \frac{sin^{2}(\pi k T)}{(\pi k T)^{2}}$$
I think that this function is a definition of sinc ...
AI: Note that \$\text{sinc}\,{\pi k T} = \frac{\sin{\p... |
H: Transformer and Rectification confusing
I've been taught that a transformer only works with AC, however I see that in power converters, it is rectified to a DC voltage before going to the transformer. How does that work?
If the rectified AC waveform is now DC, how does it pass through the transformer? Is the rectif... |
H: Stable state and don't care
I have a latch but I can't understand what are the meaning of Un/Stable state and "don't care".
I found a reference about the definition of the state, but I didn't understand that fluently.
I try to understand these questions:
Statemanet A: while Q2=1, Q1=0 we get stable state.
but why?... |
H: Would 5.5 x 2.1 mm male plug work inside a 5.5 x 2.5 mm female jack for DC power?
General Question
I am wondering, is it possible to use a 5.5 x 2.1 mm male plug inside a 5.5 x 2.5 mm jack for transferring 12 Vdc?
My thoughts are just that it may just be a tight fit on the inner conductor. It may also just not fit... |
H: Correct way to add LED in front of SSR?
Looking at at adding a simple LED indicator in front of an solid state relay. Not sure if its more correct to put it in series or use two different resistors as shown in the example. The indicator LED while close in voltage is different. The SSR is 1.25v while the indicator L... |
H: Power a guitar pedal (usually takes 9V power) with a single AA battery
This is not necessarily for real life application, but more for the challenge: would it be possible to power an existing guitar pedal (let's say a Roland / Boss saturation, fuzz, reverb, delay, etc.) with just a single AA battery?
I've recently ... |
H: Why opamp output doesn't match with the calculation?
The actual current passing the load is 44mA, in below schematic the voltage across Rsense is 454mV and the opamp output is 4.52V. which is correct.
But when I replace the Rsense with a 0.1 ohm resistor the voltage across Rsense changes to 1.9mV and opamp output t... |
H: Should I ground the unused pins of an oscillator crystal?
I have seen in this example circuit of an RTC where the unused legs of an oscillator crystal are grounded. I will be using an ECS EXC SMD crystal and from what I thought the unused pins are better left disconnected to the circuit and are just there for struc... |
H: Will my step-up converter module break if I connect a power hungry device to it?
I recently bought a step-up converter module. It is rated to work at 24 volts and output MAX 28 volts and 2 amps. I will connect it to a source that outputs 5 volts and 20 amps. If I connect a power hungry device to the module which dr... |
H: Can i use 1 fuse for all the outputs to protect my power source from overcurrent?
Can i use 1 fuse for all the outputs to protect my power source from overcurrent by connecting the fuse to the ground wire? I have 3 outputs: 3.3V, 5V, 12V and i want to protect my power source when it reaches more than 10Amps. I don'... |
H: 5 V home network
I'm planning on adding multiple IoT devices in my house, and I'm looking for an elegant solution to power them all. They'll all need 5 V, a small number of them (cameras) would draw up to 2 amperes, while most of them would draw less than 500 mA.
I'm thinking of running a separate 5 V line, through... |
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