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H: Can I reduce this AC motor speed?
I spent yesterday opening this fan unit and researching...
I'm looking to reduce the speed by about 25-40%, at the lowest speed setting only.
Please have a look at the photo and let me know what options I have?
Fyi the resistance values is 190, 260, 310
I would prefer not to do the... |
H: hFE value (a.k.a β or gain factor) for transistor, at different voltage
I've been looking into the BC337 NPN transistor, and I saw in the hFE graph on page 3 of the datasheet, that the graph was at 1 V from the collector to emitter. Is there any way to find out the hFE value for a different voltage like 5 or 10 V? ... |
H: How does a wifi antenna work?
let's consider a common wifi antenna (used in routers) like this:
I don't understand some its basic features:
1) Is it a dipole or monopole antenna? I see only one conductor, so I'd say it's a monopole. But, where is the ground plane? As far as I'm concerned, a monopole antenna needs ... |
H: Help with piezoelectric circuit
I connected three piezoelectric sensors to a rectifier which was further connected to a capacitor (100µF). I kept hitting the sensors for some time, and measured the voltage across the capacitor using a multi-meter. It displayed the voltage to be around 6 volts. Then, I used a breadb... |
H: Can this Eaton T0-2-8211/E changeover switch between multiple sources
I have this Eaton 1|0|2 style changeover switch T0-2-8211/E. Can I use this to switch between 2 different input sources?
My intention is to use it to switch between shore and generator power on boat. It's not going to be used frequently so no aut... |
H: Are BLE attribute handles constant?
Say for example you have an embedded peripheral BLE device which has a single BLE service with some characteristics and the initialisation order is always the same (service is added, then characteristic A is added, then B and so on).
In my local testing, the handles passed to the... |
H: Why does the frequency of carrier signal not matter when we impose the original signal on it?
I know we use modulator to change the frequency of original wave, thus reducing the size of antenna. As I understand the frequency of carrier signal does not matter . But I don't understand why.
AI: The frequency of the... |
H: How does a RCBO trip from a vapourised PCB trace?
I was replacing a power board with a new (plastic insulated) one, which resulted in a trip of the 20A 30mA RCBO on the circuit instantly upon turning on one of the board outlets. The built-in 10A breaker on the power board did not trip.
Since all loads previously wo... |
H: When using an open-drain output to drive an NPN transistor, can the base resistor be replaced by a pull-up?
Assuming the value of R1 is the correct value for the base resistor for the given motor L1, is it okay to omit the additional base resistor, used in push-pull applications, for an open-collector output?
To my... |
H: ATXMega ADC - What is bandgap reference and temperature?
On my ATXMega128A1U, I am using ADCA to measure an input voltage (roughly ~1.70V) and I plan to use a VREF of 2.5V. I was reading the XMEGA manual, specifically for the REFCTRL register where I would set REFSEL to 010 for AREFA as seen below:
However I am a ... |
H: Determine if phototransistor is in cutoff
I'm attempting to determine if the following phototransistor HOA1870-031 is in cutoff.
The HOA1870-031 we have in stock have the cathode of the IR emitter tied to the emitter of the IR detector (phototransistor).
What I want to do is detect whether the phototransistor is in... |
H: In an amplifier, does the gain knob boost or attenuate the input signal?
I'm thinking specifically about guitar amplifiers, but I'm guessing this applies to all audio amplifiers.
I understand the practical function of a gain knob, but what's not clear to me is whether the gain knob is simply a potentiometer that at... |
H: Why does this current not match my multimeter?
Newbie to electronics here! I have an Arduino Uno with a 15 Ω resistor connected to the 3.3 V pin, on my multimeter, it gives me 3.2 volts.
If I use this calculator:
https://ohmslawcalculator.com/ohms-law-calculator
And place values of 3.2 volts, and 15 Ω resistance, i... |
H: Debounce slide switches in verilog?
I just created my first FPGA project. I created a small FPGA PCB with some slide switches to input values to the FPGA. Sadly, I did not debounce them properly with hardware, as you can see in these oscilloscope images:
How can I debounce the switches in "soft"ware on the FPGA? ... |
H: Can't get WS2812B LED strip working with PC power supply
I am an absolute beginner in both electronics and LEDs.
I would like to power my WS2812B LED strip (5m, 300 LEDs) with an old PC power supply.
The power supply has 600W so more than enough power.
To trick the power supply into thinking it is connected to a mo... |
H: Incremental encoder - polling or interrupts?
I took over a project including PIC18f25k80 microcontrollers and incremental encoders. Basically I just need to follow the position of the motor using the encoder, and drive a device to specific locations. I know that there are more methods to read an encoder and update ... |
H: simple way to send addressable RGB signal wirelessly
So my electronics knowledge is pretty limited, But I'm hoping there is a simple way to do what I want. Also I'm sorry if this question is answered somewhere else as I'm probably not using the right search terms or something.
I have an addressable RGB LED strip co... |
H: On off switch with 2xLED
I'm trying to connect an old/possibly broken switch to a light from a 12V battery (very good first question isn't it?). The switch is meant to light Green when ON mode and Red in OFF mode.
The schema (as I traced it) looks like this but actually looks like shown at the bottom
My first ques... |
H: Generic 433MHz receiver, how to derive output signal voltage
I have a 433MHz receiver modules (Model number MX-05V) The input voltage is listed as 5V but they don't list the output voltage.
I have seen this used without level shifting in a project in conjunction with an ESP32 module that requires 3.3v signals.
In r... |
H: 2 x 90 Ah 12v deep cycle batteries in series runs 77-90w for under 20 minutes. Why?
I am trying to understand the maths here. I have 2x90Ah 12v batteries in series (24v) and they are powering my computer. The peak power is 120w while the computer is shutting down during a power loss. I get less than 20 minutes run ... |
H: What does "Not recommended for new designs" mean in an ATtiny datasheet?
I am making my own circuit and I am using ATtiny10-TS8R (I couldn't buy any another type for now), but I found (6) in the datasheet on the part I want to use:
As noted in point (6), it says "Not recommended for new designs".
I used it already... |
H: Why should we use 3.3 V instead of 3 V?
Why do we use 3.3 V in circuits? Why not 3 V? Is there a specific standard? Or do we use it because it was 3.3 V from the beginning?
I am just curious to know.
AI: Why do we use 3.3V in circuits? Why not 3?
Why not \$\pi\$ V? Why not 2.8 V, a much nicer number than 3 V? The ... |
H: In SR latch when apply a pulse to reset latch how the Q is changed?
Here is the initial state of SR latch both reset and set inputs are zero.
Here we apply a pulse to the reset input and it shows it changes in this way
first -
and then -
The thing that I don't understand how R pulse can change Q state without re... |
H: Why the euclid distance between the plates of the capacitor has been doubled to find out the capacitance?
I may have been asking of an easy problem.
The problem requires to find out the capacitance.
The ideal capacitor with area of \$S\$ exists and the euclid distance between the plates is \$d\$.
The dielectric wi... |
H: What do the markings 40/100/56/B mean on this capacitor?
I am trying to replace a steam iron capacitor which has the following markings
I know that it's 0.68 micro Farad with 10% tolerance, but I can't seem to understand the 40/100/56 marking. There's replacements online with 40/100/21 so I'd like to know if they'... |
H: Understanding voltage drop on a transistor
I've been reading different answers online and am trying to get my head around calculating transistors.
I have a circuit like this:
(Imagine the base goes to a microcontroller and is connected properly.)
After the red LEDs, the voltage will drop to 3.2V.
Will the transis... |
H: A mistake in "Op Amps for Everyone" about op amp attenuators
In Texas Instruments' book "Op Amps for Everyone" (5th edition, link, see page 347), in chapter 25 "Common Application Mistakes" I believe there is a mistake (ironically).
It states that it's wrong to use a unity-gain stable opamp for an attenuator like t... |
H: Different answer from power equations
Imagine a circuit like this: 6 red leds with a Vf of 1.8V are wired in series with a resistor. Vcc is 12v.
To acheive a current of 10mA, you would do (12-10.8)/0.01 = 120 so 120 ohm resistor.
Now to calculate the power dissipated over that resistor I have three options:
P = VI... |
H: Touch sensor with a CR2032 battery and a transistor
I'm not an electronics engineer but I have a question that may look strange to a specialist:
Can I make a touch sensor that lights a LED using a CR2032 battery?
I tried to use this circuit without the resistances and with a different power source but the LED is no... |
H: What is the resistance of this DC fan?
I opened and took out some components of an electric source of a desktop computer that doesn't work anymore (the source not the computer, I bought another source). One of them is a fan DC 12V: HA1225M12S-Z.
When I supply 12V to the welded terminals of the other side of the PCB... |
H: Can I connect the LoRa Module pin to SMA Antenna with wire?
I have RFM95W LoRa Module and an antenna with an SMA connector (you can see in the image below). The module does not have an SMA connector. There are just pins. Can I connect the SMA connector with some wire soldering to the LoRa module? Will this make any... |
H: Buck converter ouptut zero voltage
I've designed PCB which uses TPS54531 to generate 5v from 12v input. The circuit as below is similar to the reference circuit from TI.
After powered on, the VCC5_TMP read abnormal value 0 instead of expected 5v. Then I measured PH(pin8) as below which is also incorrect.
After th... |
H: Electronic components identification
In the picture below, I have a power resistor, which is powered either from 12VDC or 24VAC from the rest circuit, as well as another component, which is inserted on the one cable leading to the resistor.
My questions are:
What does each number mean on the power resistor markin... |
H: Colpitts oscillator not functioning
simulate this circuit – Schematic created using CircuitLab
I don't understand how the circuit works .I know it is a Colpitts oscillator but the part where I get confused is that in the video on youtube it says we can set Ve = 1/2VCC however I don't understand how this can happen... |
H: Arduino Due ADC sampling
I am working on an Arduino board and I have no previous experience with it, unfortunately. I need to sense the voltage signal from a sensor using the ADC of the Arduino. I have an Arduino Due manual which says it has up to 12 useable pins for ADC input. I want to acquire 4 analog signals. H... |
H: Simplification of ideal op amp circuit
For an assignment at school I have an op amp circuit where I need to get the Transfer function of. I want to ask if my approach is correct. Because it feels I simplify it too much.(R1,R2 and R3 have the same value)
If I assume the op amp is ideal, I can say that V2 is equal t... |
H: BAV99 forward voltage
I am reading the BAV99 datasheet from ON Semiconductor.
From the table on ELECTRICAL CHARACTERISTICS (page 2)
(TA = 25°C unless otherwise noted) (Each Diode)
Forward Voltage
mVdc
IF = 1 mAdc
715mV
IF = 10 mAdc
855mV
IF = 50 mAdc
1.0V
IF = 150 mAdc
1.25V
On page 3 there is the... |
H: Determining voltage by arc length
Ludic science light dimmer driver
I was watching this video made by ludic science and at 3:14 he said that at the maximum output of the high voltage ignition coil, the distance was 10mm/1cm which he claimed to be 10-12kv. Isn't the gold standard for the breakdown voltage of air 30k... |
H: Resistor circuit to correct impedance matching and attenuate signal by 10 decibels
I've got a Line Out on my amplifier with 100-600 ohm impedance (avg. 350). I have it connected to an effects pedal that has a 1M ohm input.
Right now the signal is clipping from the amplifier and I would like to attenuate that with a... |
H: What is the purpose of the fenced-off area on this board?
I saw a recent video on YouTube where the presenter describes a commercial micro-current measurement product. What purpose does this tinned fence serve? I'm guessing its for noise suppression but I'd like to know more. Is it grounded? Since the parts inside ... |
H: Primary voltage drop in current transformer
Following on from this question, Current transformer energy harvesting from a mid-voltage line, I've never seen any mention of primary voltage drop in a current transformer circuit.
simulate this circuit – Schematic created using CircuitLab
Figure 1. A typical CT applica... |
H: Inability to forward bias diode in a simple circuit
I am struggling with forward biasing a diode in the circuit in the attached.
All the wires are attached properly, as there is continuity. The diode drops only 0.400V with a 9 V battery connected, the resistor being 330 ohms. I cannot understand why the diode woul... |
H: Analogue switch TS3A475 does the direction matter?
Does the "direction" of the signal matter?
signal is 1/3Vcc to 2/3Vcc
AI: No, it doesn't. But you need to make sure that the voltage is within the range specified in the datasheet (usually it must be between the supply rails of the switch), and also the switch has... |
H: Switchable AC-DC output
So today I want to make it a little bit strange...
I'm working on a project and there are 4 outputs controlled by 4 relays and the relays' outputs are coming out of the board with phoenix so the user can use them like a switch.
But I'm thinking of putting it in a higher level so the user can... |
H: 24V with IRF3708
I've a strange issue. I wired everything up like that:
The ATTiny13 changes, for test purposes, every 10 seconds between HIGH and LOW. Since the IRF3708 needs 2.8V to switch state, I use the 5V "power line" with a transistor to get over the threshold.
FYI: This is not my whole project; but it must... |
H: Cleanest way to solar-power a string of outdoor bistro lights
I'm trying to hang some bistro lights on my balcony — specifically, the SVARTRÅ outdoor bistro lights from IKEA.
There's just one issue: the balcony has no power outlets, and I'm not going to snake a cable out my balcony door, so I'm trying to find a way... |
H: Silicon-free amplifier
I'm working on building a silicon free computer and I need a way to store information after power off. Right now, solid core memory seems like the best option. However, the sense line of solid core memory produces a very small pulse of electricity when activated, and I need a way to boost tha... |
H: Explanation for drift current
My question is why the concept of drift current or movement of minority charges is necessary while the pn-junction is formed. So drift current was explained to me in more or less this way
As the holes diffuse from p to n side due to concentration gradient, it leaves behind an ionised ... |
H: Basic Questions About a Simple Circuit (GPIO-Controlled Relay on RaspberryPi)
I want to control an 8-port Sainsmart relay from a Raspberry Pi (via the GPIO pins) and I'm trying to understand a couple of things about the suggested circuit for integrating the two. Here is the circuit:
As the explanatory text says, ... |
H: Why is the output of a high-pass filter not 0 when the input is 0?
I'm trying to design a 5th order Butterworth high-pass filter built on the Sallen-key topology with a cut-off frequency at 100Hz. For some reason, the output has a DC offset of around 5mV when the frequency of the input is less than the cut-off freq... |
H: Help identifying MOSFET manufacturer
I have a MOSFET that I'm trying to identify the manufacturer of. I know it's an IRF520N, but it doesn't behave the same as an IOR IRF520N, so I'd like to find the actual manufacturer's data sheet.
The unknown one is the one on the left.
AI: The manufacturer of the left one is a ... |
H: OpAmp/Comparator for AC current detector circuit
I am trying to complete schematic for current detector. This is addition on How to build AC current sensor circuit for ESP-01 GPIO.
By googling and researching I came with following schematic which I try to simulate in LTSpice:
For a simplicity I used V1 which is v... |
H: Trying to understand how this PNP works
I am new to electronics and still learning so please don’t be too hard on me
Here is the circuit I am trying to understand:
To control to top PNP transistor, there is an optocoupler and 2 resistors.
When the opto is off, the base of the PNP is in series with the 10k resisto... |
H: TMC2130 does not work properly
Great title, I know.
I have a driver board connected to a really small stepper motor. When I run it in step / dir mode it works.
But as soon as I connect either SCLK or MOSI the motor turns at double the rate, TMCs CS is low it turns in full speed and when CS is high the motor acts co... |
H: Deducing the equation of the circuit which is composed of batteries in parallel and the external resistor
We assume that the \$n\$ batteries have been connected in parallel, and the external resistor connecting the endpoints(terminals) of the parallel part.
\$n:=\$ number of the batteries.
\$r_i:=\$ith internal res... |
H: How do I find the -3dB point on a given graph
I just performed an AC Simulation on QUCS and was asked to find values of gain and phase at low freq. and high freq and at the -3dB frequency point with the roll-off slope. The circuit is an RC circuit as shown below (image was taken from QUCS itself)
My questions are:... |
H: Interpolation method for downsampling smartphone sensor data
I have a dataset containing lot of sensor measurements on Android smartphones, namely accelerometer, gyroscope and light sensor. The light sensor was sampled at a rate of 4 Hz and the accelerometer and gyroscopes were sampled with up to 500 Hz (depending ... |
H: Order of operations and rounding for microcontrollers
I was working on a project where I read a value from a 16-bit ADC and scaled it to obtain the reading of a sensor. For example:
uint16_t reading = sampleSensor();
uint16_t temperature = reading/0xFFFF*2.5*1000*2;
Where the ADC has a full scale value of 2.5 volt... |
H: External ADC with Arduino
I am studying Arduino ADC and I have not much background in micro-controllers. Excuse me if this question is too basic.
I found that people use external ADC for better resolution as compared to the built-in ADC of Arduino. One thing which I could not understand was the bit resolution. I sa... |
H: Differential ADC reference plane - ground or midpoint?
The Microchip (ex-Atmel) ATSAMD10 has a 12-bit SAR ADC with the option to use differential input. I'm generating a virtual ground (\$V_\mathrm{mid}\$) at the midpoint (512 mV) of the reference voltage (1.024 V), with the input signal centered around that.
My q... |
H: Inductance of air core coil decreasing due to ferromagnetic object put in it?
I have built a Colpitts oscillator which you can see in the schematic below. Note that the values for R1 and L2 are not correct since I use a self-wound air core coil for L2 which means I can only approximate the inductance with calculati... |
H: Maximum sampling frequency of Arduino (internal vs external ADC)
I am studying the Arduino ADC.
I learned that the maximum sampling frequency of the Arduino ADC ( e.g. Due) is 1M sample per second.
As the Arduino ADC has only a 12-bit resolution I must use an external ADC with a 16-bit for higher resolution.
What i... |
H: Fundamentals: The role of battery in a circuit
As I understood, the analogy of a charge moving through a circuit is similar to water flowing from a high altitude to a low altitude (like waterfalls).
But in waterfalls there are two requirements if we wanted to keep that same water repeating the cycle, we need a gr... |
H: capacitor unit is not specified
I am currently working on a circuit but I can't figure out the non-polarized capacitor values, since some of them are not clearly specified as unit magnitude.
Some of them are: 100, 500, 180, 5.6, 56, 220.
What should I use; pF, nF, uF, mF, F?
AI: Some of them are: 100, 500, 180, 5.6... |
H: Speed regulation for universal motor
I'm building a grinder, which consists of a shaft on which the grinding wheels sit, and the shaft is driven by a universal motor out of a washing machine via a belt and a pulley.
I'm using an off-the-shelf SCR speed controller. What I'm finding on the first test run is that the... |
H: LED Status Readback Circuit
Sorry for such foolish question, but what is the behaviour of circuit below:
LED_ON is 3.3V logic control signal, LED_STATUS is output signal to MCU pin (GPIO).
When LED_ON is logic high and Q1 is open LED1 is ON and LED_STATUS = '0', but what will happen when LED_ON = '0'? Q2 will be c... |
H: Output compares triggering function not work on STM32?
I've been trying for 2 days now to get my Output Compare to trigger a function.
I've been reading up on it, and there is a callback function that, from what I understand, is triggered when an output compare is triggered:
HAL_TIM_OC_DelayElapsedCallback()
void H... |
H: Data Sheet Inconsistencies with TI LM2672N
I'm a novice with Electrical Engineering, and am having a difficult time coping with inconsistencies in a particular data sheet.
Texas Instruments LM2672N-5.0 Data Sheet
Like many data sheets, TI provides example circuits for using their chip. However, unlike other data sh... |
H: Why do these capacitors have an additional plastic block around them? What kind of capacitor is this?
Just saw these type of capacitors for the first time and I'm curious :
Why do they have this additional block of plastic around them? Some kind of shielding?
Is there some specific reason they didn't just use the ... |
H: Simulating High-Side N-Channel Bootstrapping in LTspice
I'm working on understanding bootstrapping, so I copied the schematic used in this YouTube tutorial in LTspice. However, my simulation doesn't appear to yield the results that I would expect from a properly bootstrapped circuit. While the gate-source voltage a... |
H: Non Inverting Op Amp output near power supply voltage when input voltage is at 0V
I have a simple non inverting op amp circuit.
I am using this to amplify a DC voltage. The positive input voltage will vary from 0V-5V.
My problem is that regardless of the input the output is about 22V.
The exact op amp I'm using is... |
H: Must an LCD panel meet specific requirements to support a higher refresh rate?
Newer LCDs can refresh the screen at 120Hz or higher. The driver circuitry for the panel is responsible for pushing frames to the panel at a given rate, but are there any particulars of the LCD panel itself that factor into achieving the... |
H: How to correctly connect low current analog ground plane with high current analog ground plane on PCB?
I am currently designing a PCB for a PWM controller based on the LMC555 timer chip along with a low side gate driver FAN3100TSX and N channel power MOSFET. Below is the PCB in question. In my design, I have separa... |
H: Discharge rate of a motor run capacitor?
I have a capacitor on a pool pump, specs : Motor Run Capacitor Round 30 uf MFD 370 Volt VAC 12717
As I understand even with electric circuit the pump is on turned OFF, the capacitor can still carry electric charge. How do I calculate the time I need power off so to ensure t... |
H: Manually Use LEDs on RJ45 Connector
I am using RJ45 connectors(2-406549-1) with built in LEDs, to transmit SPI lines for a microcontroller project(I needed CAT 6 cables for twisted data/ground pairs).
I'd like to use those built in LEDs to notify when the PCB has power, but I can't find any information on what thos... |
H: Terminology clarification for transformer with a third primary tap
I am looking over the reference design from Microchip app note 46102, page 4, that shows a reference schematic for the M90E26 energy meter. They are using a transformer that has a series tap along the primary winding to pull 35Vrms for rectificatio... |
H: How do I create a 1-bit full adder that outputs a 2-bit sum?
I am trying to build a 1-bit full adder that outputs a 2-bit sum.
I know that the standard 1-bit FA outputs a 1-bit sum and a carry bit, but I was wondering how can I modify the FA such that the carry bit output is discarded and the only output is a 2-bit... |
H: How do I calculate the transfer function of this basic terminated RC filter?
I'm reading through an electronics book to teach myself, and I'm in the section about filters. I've been following along so far, but now I'm confused about how the author came to a conclusion in his math. Here is an excerpt from the book (... |
H: BODLEVEL Fuse Coding
I'm using ATmega1280, and I have a question about this BOD table:
what is exactly the meaning of "Min. Vbot" and "Max. Vbot"?
AI: It means that the exact BOD voltage is a little imprecise and can vary within those limits. Take the strictest limit into consideration considering your implementat... |
H: Can you explain this basic circuit to me? Why is the transistor switch off?
I am pretty new to the world of electronics so apologize yet again for a very basic question.
I am trying to understand the functioning of a transistor, but my confusion may underpin some more fundamental confusion about voltage. I think un... |
H: Does it matter if the shunt resistor in an audio Line Out L-Pad attenuator is 6 feet away from the series resister?
I am designing a 14dB L-Pad attenuator to be buried in a guitar instrument cable as per below.
The placement of the 22K ohm series resistor is to go inline inside the amplifier side of the 1/4" mono p... |
H: How much current Hold and WP SPI Flash pins can draw?
In my design J14 is used as header to which I connect wires to an external programmer (DediProg) in order to program an SPI Flash (U25).
At the time of flashing, I don't want to supply voltage to (3V3AUX) gives power to a Host Controller which needs this flash R... |
H: Rechargeable Li-ion battery pack
I'm trying to power up an ESP-01 with a Li-ion battery pack recharged by a solar panel (12 V).
The question is: can I connect the solar panel directly to the battery pack with a voltage regulator, or do I need something else as protection?
AI: A voltage regulator on its own won't do... |
H: Efficiency of a switching regulator
I have a 24V power supply line which I would like to transform to 5V (<1A) in order to supply my chips. Voltage regulators would waste a lot of energy in this range. I looked at some datasheets of such switching regulators e.g. TSR1-2450. On page 1 it is stated that an efficiency... |
H: finding corner frequency using .MEASURE in LTSpice
I wanted to find the corner frequency of this circuit :
I run the simulation but couldn't find the frequency using .MEAS AC f FIND frequency WHEN V(o)=-3dB command.
I am getting this error in SPICE Error Log :
Measurement "f" FAIL'ed
Date: Wed Jan 27 11:59:28 20... |
H: Optimising a single pulse precision peak amplitude detector
So I made this precision peak detector circuit (with reference from EEVblog's video and experimenting with the resistor/capacitor values), with which I want to measure the peak amplitude of a single pulse of width 5us (50ns each rise/fall time at best and... |
H: Significance of the center-tapped transformers in mixer circuits
How does center-tapped transformer work on the circuit given below?
In analog rectifier circuits, one of ports of the center-tapped transformer is connected to a sinusoidal source while others are driven with a DC source or ground. But in mixer circui... |
H: DC motor doesn't start until PWM duty cycle exceeds threshold but continues to run when duty cycle reduced below threshold
I'm using a DC gear motor (from this kit, plastic gears) driven by a L298N module controlled by a STM32 BluePill. The motor voltage supplied to the L298N is 9V from a variable voltage AC adapte... |
H: Voltage drop over MOSFET controlled by microcontroller
I made the circuit below to power a microcontroller and a load from one power source.
But looking at the voltage drop between drain and source of the IRLZ44N MOSFET, instead of 12 V I got only 3.1 V when the MOSFET is opened by ATtiny85's 4.5 V signal.
What am ... |
H: 20 dB/Decade - Justification
I've read that it is recommended to have 20 dB/Decade slope on the L(jw) magnitude plot of the Bode Diagram at gain crossover. This seems to imply a slope of -1 in dimensionless terms.
However, what is the justification for this? The reasoning for this always seems to be glossed over.... |
H: IC to use for multiplexing SPI chip select
I have a number of SPI ICs but limited GPIOs on my microcontroller, so want to multiplex the CS pins to something that requires only a couple of GPIOs. I use the predetermined clock, MISO and MOSI on the microcontroller.
My initial thought was a ring counter, but all the ... |
H: Smart load switch with inrush control and overvoltage lockout
After I finish making my dc-dc buck-bost converter, voltmeter and ammeter I decided to add a smart load switch to my power supply in order to have the posibility to connect electric motors, bulbs or any element that generete big inrush currents at startu... |
H: 555 timer capacitor charging order
I have a question about the standard 555 circuit below. I understand to some degree the "insides" of the timer. In particular, I understand the role the comparators play and I am fairly certain I am able to follow the logic as the voltage going into pins 2 and 6 increases.
My main... |
H: How to determine the power rating of an output LC filter
I am trying to design a Class-D Amplifier using the TPA3116D2 IC chip. Using the typical application circuit provided by the datasheet on Pg.26
Everything is going well with the support circuitry but what's getting me all stuck is the "OUTPUT LC FILTER" sect... |
H: RISC-V assembly lui?
In RISC-V assembly I wrote:
addi s0,x0,0x20000
Is this legal such that the assembler will prove the command and make it work right or I'm forced to change it to:
lui s0,0x20
Can someone kindly explain what lui does?
AI: No, this won't work because ADDI can only add 12-bit immediate values whi... |
H: Transfer function of two inputs?
Suppose I have a system with feedback. Consider the input \$d\$ that represents disturbances to the plant; also, consider the input \$V\$ that represents sensor noise on the feedback loop. I can calculate the closed-loop transfer function \$\dfrac{Y(s)}{d(s)}\$ and \$\dfrac{Y(s)}{V(... |
H: What is the specific reason for using FIFO in the asynchronous domain in VLSI?
I was wondering that the reason is of using FIFO in the asynchronous domain in VLSI.
Basically, to prevent x propagation in the asynchronous domain (aka CDC domain), it was taken care of by the two-stage F/F method for resolving the issu... |
H: How to find SMD resistor and capacitor value and correct size
I'm new to the SMD world and struggling to find an easy and quick way to get the correct SMD resistor and SMD capacitor size and value based on a circuit schematic; any tips will help.
For example, I'm designing this circuit in SMD but don't know how to ... |
H: How to calculate impedance of a PCB trace Antenna in Altium w.r.t. a given frequency?
I am keeping things abstract as I intend to learn and not just copy another design.
So, suppose I am trying to design an antenna of impedance Z and frequency f.
Now, in Altium 18, there is a feature that suggests trace widths for ... |
H: Electrical work sign convention
If I understood the correct sign convention it's as shown in the below sketch
AI: Your sketch is right.
Positive charges do repel each other. So moving two positive charges closely together needs some positive work to overcome the repelling force.
A positive and a negative charge do... |
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