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H: Resistor in shunt regulator not following Ohm's law?
I was reverse engineering a power tool battery charger (21V SMPS) that derives its 5V rail from a simple shunt regulator, employing a TL431 programmable precision reference and a NPN transistor, as per my crude sketch (sorry I didn't have time to paint it). The ... |
H: How do you choose a PWM Frequency to drive a DC motor?
I can clock the PWM to drive motors at most any reasonable frequency, but is there a "best" PWM frequency for motor control?
What must be considered when choosing a PWM Hz?
Is there a most efficient Hz per motor?
If so, is there a way to calculate that based ... |
H: How to find the best settings for Cyclic voltametery test?
I am trying to conduct a CV TEST (Cyclic Voltammetry). However, I am unable to get the current peaks on my plot. I tried different ranges of Voltage at different scan rates. However, I could not achieve any meaningful full result. can the test be successful... |
H: Logic Input Current Definition
I want to control shutdown pin of this IC MAX9920 using digital output of arduino.
https://datasheets.maximintegrated.com/en/ds/MAX9918-MAX9920.pdf
My question regards to this:
In the datasheet page 6 says shutdown input current max 10ua. So if digital output of arduino when is high i... |
H: Step down variable high voltage DC input to low voltage DC output
I'm looking to find a system that will help me step down a high voltage DC input to a low voltage output. The problem is that the DC input in question is not very stable in terms of voltage and varies depending a number of situations out of my contro... |
H: Reading oil pressure switch from motorcycle with Teensy (Arduino)
I'm trying to read a oil pressure switch (I'm actually not sure about the sensor type) from my motorcycle (ZX6R) with a Teensy 4 board (Arduino like).
Here is a picture from the electrical schematic:
Measuring BL/R to ground with a multimeter it loo... |
H: What is meant by static and dynamic loads in electrical drives?
What is the definition of a static load and a dynamic load when it comes to electrical drives? Can someone give some examples for both types of loads?
AI: Dynamic load is meant a torque required to accelerate/decelerate the mass/inertia. A static load ... |
H: 1 voltage regulator for all components or 1 voltage regulator for each component?
Is it a good idea to only put 1 5volts regulator to power all components or 1 5volts regulator for each component? If I only put 1 5volts regulator to power all the components would that affect, reduce or divide the 5 volts to power a... |
H: Flowing back of current from capacitor filter to full bridge rectifier
Context:
Pg-485 of this pdf
Now we shall discuss the role of
capacitor in filtering. When the voltage
across the capacitor is rising, it gets
charged. If there is no external load, it remains charged to the peak voltage
of the rectified output... |
H: Mosfet thermal problems in linear applications
Modern power FET's can be unreliable in some linear applications due to thermal instability causing die hotspots and premature failure. This is called the Spirito effect. How do Silicon Carbide devices compare?
AI: Several SiC MOSFETs I've looked at are worse than most... |
H: Relay flyback protection
Is this the correct way to put a diode for flyback voltage protection to protect the infrared heater? And do I need to put a flyback protection for the Arduino pin or Vcc?
AI: Flyback diode is there to avoid voltage spikes when an inductive load is turned off.
In your case, only the one on... |
H: MOSFET switch not stable
I used an IRFZ44N MOSFET to build a switching circuit to light up a bulb from a 12V car battery.
It works but it is not stable.
When the bulb is off, after a while it glows and increases.
When the bulb is on, little by little it goes dim.
First I tested it on Proteus and then I did it with... |
H: Transformer different resulting current and voltage than expected
I am uncertain why the current on the secondary side does not follow the equation:
$$i_2 = \frac{N_1}{N_2} i_1$$
which gives
$$i_2 = \frac{20}{3} i_1$$
To measure the current I use two 1 ohm resistors (one on the primary side, and one on the secondar... |
H: What is this part in the image?
I'm fiddling with a toy and I found this part. I think its purpose is give feedback to a microcontroller about the angle of the DC motors.
This is the part:
This is how it's placed with the motors:
This is where it goes on the main PCB:
I hope you know this part. I don't know how ... |
H: Transmiting analog signal with lora
I want to transmit an analog signal over Frequency Modulation with a Lora RA 02 module. First thing I need to do is convert the analog signal from the audio source to digital, right?. But I had so problems with it since Lora use Chrip Spread Spectrum (CSS). I can't hear my audio ... |
H: PCB 6-layer stackup problem
I'm currently designing a PCB with double side components and I'm limited to 6 layers max. The project has couple of MCUs at 84 MHz. There are USART, I2C, SPI, some analogue lines and high-power lines in the design but not any high-speed lines. There are also some very short RF lines for... |
H: Can someone give me some insight on how to simplify this problem?
It is hard for me to understand how to start solving this problem. Should I start using the superposition theorem? Can it be simplified before?
AI: Superposition is a good thing to try any time you have multiple sources. In this case, it's mandatory ... |
H: Help fixing a power switch
While disassembling a Sega Saturn to clean it, I removed this power switch:
I needed to separate the top grey button (1 in the image) from the rest of the switch.
After verifying with a multimeter that there wasn't any dangerous current on these components, I pulled like an idiot piece 1... |
H: What is the distinction between software & firmware?
I've started learning about embedded coding. The words 'firmware' and 'software' are a bit ambiguous to me still. My understanding is that software is high level language tailored for user interaction, loaded into the CPU and modified frequently; whereas firmware... |
H: How to parameterize a clock divider?
The best clock divider is a PLL inside a FPGA. But the number of PLLs are limited. And sometimes using of counter to divide a clock is justified:
reg [7:0]counter = 0;
reg divided_clk = 0;
always @(posedge clk) begin
if(counter == DIVIDER - 1) begin
divided_clk <= ~d... |
H: How to calculate the \$\mathcal{H}_2\$ norm of a second order transfer function?
I'm having trouble to calculate the \$\mathcal{H}_2\$ norm of a second order transfer function
$$H(s) = \frac{\omega_n^2}{s^2+2\xi\omega_ns+\omega_n^2}$$
where \$\xi>0\$ and \$\omega_n>0\$. I know that the \$\mathcal{H}_2\$ norm is giv... |
H: How to design a square wave inverter circuit without an op amp
I am using an NE555 timer circuit to generate a 0 to 12 volt 10kHz square wave.
I would like to invert that square wave (so inverted signal is 0 when original is 12V and 12V when the original is 0 V.)
I used an NPN transistor that creates a distorted in... |
H: n-channel JFET: importance of gate drain voltage (Vgd) and validity of negative drain source voltage (Vds)
We always consider the gate source voltage as this determines the Vgs,off. But how come the Vgd doesn't have the same effect?
Following from this (and more importantly) why can't we have a negative Vds for ... |
H: Device to detect current (for cable including hot, neutral, ground)
I am trying to determine if an electrical device is on in a non-invasive way using an arduino. My understanding is that devices like current transformers and Hall sensors must enclose only the hot or only the neutral wire.
Am wondering how products... |
H: Making a simple calculator with ATMEGA32
I try to create a calculator with ATMEGA32 but it did not work correctly! For example it do operations like this (2/1=0),(5*6=12808),(22+88=12746). I know that something is wrong but I cannot find it so I need your help. Many thinks
while (1)
{
// Fkeypad is a function w... |
H: How can I verify the max power theorem in a buffer opamp?
I was thinking since the buffer makes the output follow the input the power should be the same in a buffer opamp circuit and a resistive load.
There is the next circuit (the expected power was .5W, and besides the wattmeter is bad connected, I dont know why ... |
H: How to apply Thevenin's theorem to the equivalent two-port circuit of receiving antenna?
This circuit is adopted from page 633 of the book of "Field and Wave Electromagnetics, 2ed" written by David K. Cheng. According to his description:
The equivalent internal resistance obtained by Thevenin's theorem should b... |
H: Reason behind the naming convention for the non-gate terminals of JFETs?
Why, for an N-channel JFET, is the source terminal defined by convention as the non-gate terminal with the lowest voltage? Why does this convention swap for P-channel?
AI: For an n channel J-fet it is the voltage between the gate and the lowes... |
H: Transistor turns off only after a delay
I'm building an IC programmer (for the AS5043 sensor) that requires two voltage levels; 5V and 7.5V. I decided to control those with two PNP transistors. I'm controlling them from a 5V microcontroller.
The programming scheme requires a 2us pulse for each bit.
For the 7.5V lin... |
H: How to remove huge spikes in current
I am making an DC to AC converter circuit in LTSpice. The schematic is posted below.
When I plot the current across the transistors, I get huge spikes in the current, as seen in the diagrams below.
We want to get rid of these spikes in the current.
When we built this circuit in... |
H: are all 18650 batteries interchangeable with one another?
I recently bought a PowerTac E9R-G4 flashlight that uses 18650 batteries. Replacements can be bought on amazon.com fairly cheaply.
The box the flashlight comes in and the manual, however, both say "ONLY USE PowerTac 18650-3200mAh High Drain batteries".
The b... |
H: What are some reasons for hand painted dots on chips?
I've seen lots of products with hand painted dots or markings on chips, what do they often mean? Obviously I understand everybody has their own reasons but could it be an industry common practice for QA or programming?
For example, this picture of an Xilinx CPLD... |
H: Altium Shortcut to cycle through all PCB layers one by one
I wonder if there is any shortcut in Altium to cycle through all layers of a multilayered PCB one-by-one? That is to say that when the shortcut is first entered 'Single layer mode' is selected and only one layer is displayed first and then when the shortcut... |
H: Single Value range is not allowed in packed dimension
I have been reading about packed and unpacked dimensions in systemverilog from https://www.chipverify.com/systemverilog/systemverilog-arrays, in the following code I just want to use a memory array of 64 bits width and 256 depth. This will be used in a testbenc... |
H: Why do European motorized appliances draw less inrush current than their American counterparts?
I have been trying to tease apart the history and evolution of arc fault circuit interrupter requirements, and in the process, came across a curious historical sidenote early in its genesis, namely that the use of a 5x-o... |
H: How are these layers like LCD added in Altium Designer?
How are these layers like "LCD" added in Altium Designer?
My Altium version is 21.
AI: They might be new layers added and then given names to suit their application. Or they might have had other names and got renamed like this: - |
H: CP2102 bypass capacitors
I'm using planning to use CP2102 as an USB/UART transceiver. Datasheet (can be found here: https://www.silabs.com/documents/public/data-sheets/CP2102-9.pdf) on page 21 shows example of self-powered schematic, and that's exactly my scenario: external 3.3V LDO regulator which feeds several I... |
H: How to see the solder mask layer in Altium PCB?
Is there a way to see the solder mask layer (green coating layer) of a PCB in Altium? Is it a mechanical layer?
AI: It's called "T-Solder" (top) and "B-Solder" (bottom) by default, and you can toggle visibility like any other layer. They're not mechanical layers, they... |
H: What is the name of the translucent substance on the PCB?
PCB on photo is from the Kinesis Advantage keyboard. I need a similar substance to remount the PCB. What substance should I use?
AI: That looks like hot melt adhesive, i.e. glue. |
H: Why don't transformers burn?
I don't know how transformers work but the primary coil has a closed circuit. If there is 0 load on the transformer it would short circuit
AI: If there is 0 load on the transformer it would short circuit
This would only be true if you connected the transformer to DC source (and the coi... |
H: Why do we have a limited bandwidth in electronics?
I've been looking around a bit on optical communications and it is said that the main advantage in using optical communications, namely optical fibers, lies in the gigantic bandwidth available, when compared to the few GHz that electronics can manage. My question i... |
H: DIAC datasheet's circuit is not in series with TRIAC's Gate
Being my first time to use a Triac and a Diac to control an AC signal, I read many questions/answers in this forum related to DIACs controlling TRIACs, all being very helpful.
Now, I see in a MOC302 DIAC's datasheet page 8, something that I dont understand... |
H: Why is the light emitted by the LED not of a single wavelength but consists of a narrow range of wavelength instead? Spectral linewidth change?
I do understand that the wavelength of the lights depends on the energy gap of the semiconductor, but why does it consist of a narrow range instead of a fixed value? is it ... |
H: MBI5026 led driver datasheet question
I've bought many MBI5026GF driver ICs.
based on the datasheet, the IC set up with MCU and other components is very similar to 74HC595 (Serial to parallel procedure) but with 16 bits of data per IC.
but I don't understand how the LE pin works. (it's supposed to make the latching... |
H: Are these inductors or resistors and what function do they serve?
Some context: I'm trying to learn about ways to reduce EMI's effects on microcontrollers. I've got a Telemecanique logic module and decided to open it up to investigate.
I found myself with these:
Are those inductors or resistors rated for higher p... |
H: Capacitor charging curve when using a voltage regulator with current limiting?
Most voltage regulators have output impedance in the low mOhm range, some also have internal current limiting circuits.
I want to know what the charging curve of a large capacitor might look like when connected to a voltage regulator out... |
H: What are the connectors CN11 and CN12 on STM32 Nucleo-F103RB used for?
On the STM32 Nucleo-F103RB board, there are two connectors on the upper part named CN11 and CN12 respectively. Next to them there's a text that says GND, but if they are grounded why do they have jumpers on them? I couldn't find any relevant inf... |
H: Understanding how this bi-directional logic level shift works
I'm having a bit of trouble understanding how this logic level shift circuit works exactly. The design is from Sparkfun.
Hhere is the schematic:
For my application, the LV and HV are the 3.3V and 5V bus respectively. The LV1 and HV1 are the respective l... |
H: Split wires for the purpose of measuring high currents
According to I need an amp meter that requires no splitting of the wires there is an accessory that splits wires for the purposes of measuring current.
From the looks of the device it's limited to 110V/15A circuits (or maybe 110V 30A at most). I need something... |
H: PCB designing consideration of high speed (0.5 Hz) relay load switching
Can this design cause any problems? I'm planning on switching 75W (220V) loads with this relays. I'm using 10 such relays and terminals (HB9500M). Note that it's highly unlikely all of the relays to be active at the same, even if they do, it w... |
H: Battery charging with boost converter topology
I'm designing a circuit for battery charging, which will make use of boost converter topology. I have determined the input/output voltage and current parameters for the circuit. If I put a resistor at the output with value of V_out/I_out, the simulation works just fine... |
H: 320x240 dot matrix LCD power connection
I'm interested in buying some LCD for my amateur Z80 retrocomputer, and I'm searching for 320x240 dot matrix screen with 8-bit parallel bus.
What is common for them all, they need 3 independent power connections: for logic, LCD itself and backlight... and for LCD the voltage ... |
H: Overdischarged 18650s and a TP4056 module
I disassembled an old laptop battery and found 6 Sanyo K29B 18650s.
All of them have a voltage of <= 2.5V.
When I tried to charge them with a TP4056 module, while measuring the current, the module provided 500-700 mA and got the battery to 3V in under 15 seconds.
Are these ... |
H: Simple CPU with lots of RAM
Chips like the ESP8266 or ESP32 typically only have a couple of hundred kB of RAM. Alternatively, you can buy boards with chips like the NXP i.MX 6, with which you can have gigabytes, but suddenly you're at the level of "embedded Linux" in terms of complexity, and it also looks fairly ho... |
H: Bridge rectifier: What is the purpose of these two elements?
I found the following circuit in a random video (don't know what it's worth) and have two questions about it. I get that it's a full wave rectifier, and I think I have a decent idea on how it works. However:
What is the 220k resistor for?
Why put the 105... |
H: Is this component in falstad a tl431
I'm self studying electronics, I am now familiarizing myself with the tl431, which is pretty much a "variable zener" aparently.
I was shown the following symbol.
I would like to simulate some circuits with it on falsad, I found this component, that looks pretty much alike and i... |
H: Multiplication of two binary numbers in fixed point arithmetic
I'm performing some operations with fractional numbers in a 16-bit FIXED-POINT processor.
I have to multiply the numbers \$ x=-6.35 \$, represented in \$ Q_{11} \$, and \$ y=-0.1 \$, represented in \$ Q_{14}\$.
First I represent the numbers in the resp... |
H: CSMA/CA - What happens if a faulty WiFi station does not silence itself when an RTS/CTS is received?
In a WiFi network, assume a WiFi station does not silence itself for an RTS/CTS reception from other stations and it keeps on transmitting. I have few questions related to this scenario,
1.Will that affect the whole... |
H: Can I use this power cord with my charger?
my original power cord I got with my laptop charger stopped working recently.
It had a power adapter rating of 10A/250V, and the part which plugs into my charger had a rating of 2.5A/250V.
I just got a new power cord and just noticed the ratings:
Here's my charger power r... |
H: Convert 60V AC 50Hz to 60V AC 25Hz
The setup is a 240V 50Hz AC transformer outputting 60V 50Hz AC. Connect this power supply (with a push button) to an old telephone and it rings the bell on command, but unrealistically fast.
I need to take this 60V output and reduce the AC frequency to 25Hz so the phone sounds mor... |
H: Circuit for Atmel (now Microchip) Single Wire Interface (SWI) using actual TTL UART?
Atmel defines a Single Wire Interface (not to be confused with 1-Wire) for their ATSHA204 chip.
AVR274 describes how to use a UART for SWI. But how to wire a generic TTL UART for this?(for example from a Raspberry Pi) Is it really ... |
H: ABCD parameters
I am trying to get the ABCD parameters of these circuit but I have no idea about how to solve the circuit. All I know is
V1=AV2+BI2
I1=CV2+DI2
But here no impedance is connected. If I short the output,V2=0 then what is B? Please help me out.
AI: Generally, in matrix form, for a two port network we h... |
H: Is the antenna gain time dependent?
Premise
The antenna gain of a transmitting antenna relates its radiation intensity U(θ,ϕ) to its input power as shown in the following formula:
$$G(θ,ϕ)=\frac{U(θ,ϕ)}{P_{IN}/4\pi}$$
Where the radiation intensity in far field zone is related to the frequency domain poynting vector... |
H: selecting the footprint size of ceramic capacitor for MCUs
I have noticed there are different sized(SMT foot print size) ceramics capacitor with same voltage and capacitance ratings. I have been told that smaller the footprint, smaller the parasitic inductance and parasitic resistance a capacitor would have.. does ... |
H: Two layer FR4 PCB: should you place GND pour on signal layer?
Talking about two layer PCB's FR4 due to lower cost:
I always poured ground on both layers of the PCB, I believed "the more the ground the better", but Recently I started watching altium live presentations, and I came across this video gem to 40:23,. In ... |
H: Forcing a Buck Converter IC to behave like a Boost Converter
I recently thought of a way to force the LM2596-ADJ buck converter IC to behave like a boost converter, just as a fun experiment. Let me explain the idea (I would like to get your opinions before I actually build it.)
This is the schematic block diagram o... |
H: Can't get ADC chip to work
I am connecting a 10k potentiometer to an ADC chip (LTC1273BCN) that has a 12-bit parallel output, like in the diagram at the end of the post. The 12-bits will be connected to an FPGA input bus after I can get it to work correctly. The ADC chip circuit is powered off a stable 5V from a la... |
H: TVS with low Vclamp margin
Thanks for your support in this forum.
Currently I have a couple of PCB that I need to provide a double input power supply and transient protection.
The specs for this couple of PCB are Vin= 9 to 17.5V. (12V nominal), consumption is about 18-24W/each (working mode dependent).
Long cable r... |
H: Serial port from PC not reaching the MCU
I'm trying to send some data from the PC to my STM32L432KC Nucleo board using UART.
Transmitting data to the PC works just fine, I'm receiving data through the STLink Virtual COM Port which I can see using any Serial Monitor like TeraTerm or others.
The problem is with RECEI... |
H: Capacitor voltage equation (partially charged initial state)
Assuming we have a RC circuit:
simulate this circuit – Schematic created using CircuitLab
We don't know the voltage of the capacitor but we know its voltage isn't greater than the battery voltage.
If the capacitor is completely discharged when we close ... |
H: What is this component? 1970s electronics
I broke it while trying to repair a nearby component on a 1970s board. It has two wires at one end that look like they are going to a coil and two axial wires. One of the axial wires came out with some pieces of glass.
The only markings are "P/F" which mostly likely means P... |
H: Anything wrong with connecting L298Ns in parallel?
Although L298Ns are very inefficient, they're very cheap. I have two motors that require 4A+ current at load combined. Can I connect multiple L298Ns in parallel in this way to increase the overall current output? Am I going to run into any problems?
AI: I am not en... |
H: Theory: Can power cables induce AC voltage in human body?
In a demo video (which I unfortunately can't share) a man makes the following setup:
Multimeter on 200 V AC settings with one pin in the ground socket of a conventional mains power socket.
Right hand holding the other pin
Left hand free to hover over or t... |
H: Calculating resistance in theory
I'm studying about calculating the Equivelant Resistance in some circuits and I haven't figure out how to calculate this one
I thought the way to go was to do 4k + 6k + (Req(R2, R3, R4) in parallel with 20k), I guess I was wrong since the answer is 22k Ohm for the total resistance ... |
H: LTSpice "Error:undefined symbol in:" problem
Below is my schematic for a relay SPDT symbol I’m creating. I've posted this question in the Digikey forums, but I am not sure they actually answer LTSpice questions
You may notice I’m not yet very proficient with LTSpice. Getting past that, You’ll notice the spice dire... |
H: What is the difference between 2N7000 and 2N7002 MOSFETs?
Is there any difference between 2N7000 and 2N7002? Can I replace them without changing pre-existing circuits, beside physical/package sizes? Normally for a 2N7000 I use a 100Ohm gate resistor and 1.2MOhm gate to drain resistor. Is it the same for a 2N7002?
... |
H: How are irrational numbers best represented and processed by computers?
My question is closely related to this one: How do computers understand decimal numbers?
However, that question deals with rational numbers only. I was wondering if irrational numbers can be represented by computers.
Irrational numbers are numb... |
H: Issues with kitchen fan - how to salvage?
In my kitchen there is a fan to extract air in case it smells during cooking to not make the whole appartment stink like food. When I turn it on, it looks like it is working. But after a bit of time, the sounds it makes change - which seems unexpected.
So I took the blower ... |
H: Solar load sharing for an MCU
I understand P Channel MOSFET operation and was reading this question which shows this circuit:
but I wasn't sure whether this can be used to load share with an MCU such as Arduino or ESP32 which have a System Load of 5V/3.3V respectively. With a solar panel outputting 6V, the MOSFET ... |
H: Voltage reference output impedance calculation
I'm using AD7190 to sample 4ch single-ended signal. The datasheet suggests ADR431 or ADR421 as voltage reference for AD7190. However, an article on Analog Dialogue gives a way to calculate whether an additional output buffer is needed for voltage reference.
The article... |
H: A DC current through a inductor does not create electric fields
While studying about electric fields and magnetic fields I came across this picture:
and this:
from this website and it indicates that there is an electromagnetic field around the loop of wire, while it gets powered from a battery.
Now correct me if ... |
H: Why is the collector region doped?
As long as within the active region the collector-emitter junction is reverse biased, is there a purpose for which the collector must be doped? Moreover, not only that it is doped, but it is moderately doped, thus more than slightly doped like the base region.
AI: The essence of t... |
H: Do the high / low levels of an I²C slave's response have to be of identical voltage as the levels of the I²C master's message?
I've got an IC (a TDA7318) with an operating voltage of +9 V. It's gonna be controlled by a Raspberry Pi 3B (output signal voltage: V_high = 3.3 V). Now I'd like to make sure that the respo... |
H: Water detector with a BC547 and help understanding transistors
I have set up a basic water detection sensor using a BC547 transistor to switch on an LED if there is current between two electrodes (which are spaced about 1 cm apart):
I'm trying to understand more about how transistors work. I have some questions w... |
H: Old Variac -- chassis ground? is it safe?
I've got an old (vintage!) GenRad Variac (below) that has two prong plug and two prong socket. I want to modify it to add a safety earth pin to both input and output. In doing so, I opened it up and have realized the circuit runs through the metal chassis itself, and I'm co... |
H: Are SiC Mosfets better than Si Mosfets for Solar Charger in max 550V Range
The charger needs to handle the solar array's output of max 550V, but also efficiently handle lower voltages as weather/etc conditions degrade -- down to roughly 150V. It needs to handle between 15 - 50A. Thats quite the wide range of voltag... |
H: Is there something wrong with this irregular clock line (SCL) on I2C? ( Arduino board)
I am trying to get this ADXL357 eval board to work, in connection with either Arduino Uno or Due via I2C. Sometimes I get a connection and can read out data, however often there are problems with setting up the device and I canno... |
H: Clean/reduce static in electret microphone caused by "dirty" Raspberry Pi pin output voltage
I'm currently trying to wire up an electret microphone to a Raspberry Pi. I just figured out how to wire it up to a button cell battery after a couple of days of struggling. Still learning electronics so bear with me.
simu... |
H: Need help with identifying transformer ratio
Does the transformer ratio 240:15 or 240:30? It's a bit confusing
AI: It's 240:30 with secondary centre-tap.
You might find it specified as "primary 240 V, secondary 15-0-15 V" which gives a clearer idea of how the secondary is configured. |
H: Can I connect 24V direct to optocoupler?
I would like to check sensor signal on MCU. Sensor signal is 24V. Therefore, i want to use optocoupler as an interface between MCU and sensor. NC1 is going to MCU pin. My question is if i can connect 24V direct like this. There are total 4 inputs exactly same.(24V to 5V)
I h... |
H: Is a bit error rate close to 1 just as desirable as one that is close to 0?
Let me explain the premise. If you have a communication system, and you know with a very good confidence margin what the bit error rate is, would you be able to exploit the properties of high bit error rate by simply flipping the bits? For ... |
H: Why recommend tantalum over ceramic capacitor for voltage regulator?
The LM1117 voltage regulator datasheet recommends using tantalum capacitors on the input and output. What is the reason for this? What advantage does tantalum have over a ceramic capacitor?
A 10μF tantalum capacitor costs about 21 cents, while a... |
H: Bidirectional TVS supressor instead of Snubber for Triac
I am planning on building my own smart home socket and I want to mainly control LED lamps. But of course I can't make sure that someone is not plugging in let's say a toaster into the socket. (Yes I know that I could warn everyone since it is only for private... |
H: Is there a standard way to probe SPI without causing data corruption?
When I connect my oscilloscope probes to my SPI lines, the line voltages get affected a lot and so my SPI comms fail.
I am using a breadboard as an intermediary between the two devices and adding cables to the breadboard to scope from.
Is there a... |
H: Daisy Chain USB Devices with USB2422
I'm designing a keyboard and I want to be able to daisy chain another USB device through it. I have a Drop ALT that does this and I really like it. It has two USB C ports and you can connect either one to the computer and use the other as a pass through. It uses a USB2422 as the... |
H: Single pole triple throw analog passthrough
I have a circuit that will simulate a device.
The device in question normally communicates by adding/removing resistance from a generated signal, the source of the signal will then measure the voltage difference and interpret that as a message.
In order to simulate it, I ... |
H: Monostable circuit with 1 hour high output
I want to build a monostable circuit (a circuit with one input as a pushbutton), that will output logic '1' when the pushbutton is pressed for one hour (with the least error possible) then go back to its original state of outputting logic '0' until the pushbutton is presse... |
H: How to find the voltage at the circled node
I have this circuit. The voltage source is 4V and the current source is 2A with the 2ohm resistance.
I got the node voltage at the circled node to be +8V from a circuit simulator.
Can someone help me on how to arrive at that +8V on that node intuitively and mathematicall... |
H: Amplify difference between two photodiodes
I have two adjacent photodiodes in photovoltaic mode, with two transimpedance amplifiers. Unfortunately, my MCU (nRF52840) is one meter away, and I expect a fair amount of noise to enter the system. For my application, the only relevant data is the difference in luminosity... |
H: Why is NMI commonly pulled high on many ARM SoC schematics?
I've noticed that "AP-NMI" is pulled high on several ARM SoC schematics, and it is pulled high by the real-time clock (RTC) voltage, which is an always-on power domain (battery backup). Why is this?
I've also noticed that without NMI being pulled high (no ... |
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