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H: Can a vertical multiwatt package be bent to lie horizontal after it is installed?
I am working on a project with a multiwatt package audio amplifier IC.
Can this component be bent over to lie horizontal, flush with the PCB, after it is soldered into place?
AI: I’m going to assume you have a very tight space require... |
H: DHT22 issues at 3.3V - What else could I try?
I'm attempting to use an DHT22 at 3.3V for a very low power application - remote sensor unit with a very long battery life. Currently it's on a naked breadboard with a 328p.
At 5V in a spare arduino uno the DHT22 works fine. At 3.3V... it doesn't. Things I've tried:
... |
H: Power converter: Why we always focus on loop gain involving control to output transfer function?
While measuring loop gain using AP300 frequency analyzer, why we always focus on loop gain involving control to output transfer function?
Is it because input to output transfer depends on power stage and not important ... |
H: How does the power transistor with antiparallel diode behave?
Let's say I have a transistor with an antiparallel diode in a circuit with inductance. Now suppose that the antiparallel diode conducts an intertial current of the inductance \$i_L\$.
During this time period a control signal to the transitor is send e.g... |
H: Opto / MOSFET switching question
UPDATE: To reflect evildemonic's comment.
ORIGINAL QUESTION:
I have this circuit.
The goal is to be able to put different high voltage rails into the circuit with this 3 pin screw down connector. For example I am going to put 12 V in on pin 1 on HV1. I am then going to be able to ... |
H: Laplace inverse transform of an exponential multiplying another function
I was trying to understand the inverse transform of \$Y(s)=F(s)e^{-as}\$, but on different sources I found three different answers (H being the step): \$f(t-a)\$, \$H(t)f(t-a)\$ and \$H(t-a)f(t-a)\$.
The first and the second I guess could be t... |
H: How to calculate the voltage on this photodiode cathode?
Given these values, what steps to take to calculate the voltage present on the diode cathode?
V_bias = 100V
R_s = 700k
C_d = 1 uF
Diode dark current = 10 nA
Diode capacitance = 50 pF
AI: By "voltage" do you mean the operating point? Without knowing the time... |
H: AND gate output stuck at low
I am using a SN74HCS09 Schmitt-Trigger AND gate that has the output pins stuck at low. Despite trying different combinations of high and low channel inputs, the outputs remain stuck at 0V.
I am supplying 3.3V for VCC and have a capacitor at the supply. I have tried 10k pull-down resisto... |
H: Help with voltage regulator
I’m very confused on how a voltage regulator is used. On this one that I found: Fasizi 3.3 DC Voltage Regulator 4.75V-12V to 3.3V 800mA, I have no clue where which cables should go where. If I use a USB cable, where do the data+ and data- wires go? There are only 3 pins on it. Or do I on... |
H: Fundamental Question - how does magnetic permeability work for weak signals?
This is basically a physics question. If a sophisticated answer is needed, please go for it.
The standard explanation of magnetic permeability is something like this:
In a ferromagnetic material, there are many small regions of the materi... |
H: What schematic symbol is used for a flex cable?
Generally asking, but primarily for KiCad, what is the schematic symbol typically used for FPC/FFC/flex cables?
That is to say, the flat end which is sometimes stiffened and does not have a connector like in the following image:
In KiCad, would the above cable be rep... |
H: Understanding voltage in simple electromagnet and DC motors
I made a simple electromagnet with enameled copper wire wrapped many times around a metal allen wrench. I attached the electromagnet to my PSU and it works great, but I do not understand the voltage output.
I understand that the magnetic flux is proportion... |
H: Regulator voltage drop upon connecting a relay
I have used an LM7805 as a voltage regulator from approx 36 V to 5 V. The regulator initially outputs 5 V perfectly but as I add up a single relay the voltage drops. And upon adding 2-3 relays in parallel the voltage further drops. Although for other types of load, the... |
H: How can I do immediate addition in the Atmel AVR instruction set?
I've been doing some AVR assembly programming for a university course, and I recently happened upon a situation where I would have wanted an "add immediate" instruction. However, no such instruction seems to exist within the Atmel AVR instruction set... |
H: Why does this datasheet report negative values for the gate threshold voltage?
I am a bit surprised to find negative values for the gate threshold voltage in the datasheet of an n-channel MOSFET, reference BSS159N from Infineon.
Since it is an n-channel, I would expect positive values instead. What am I missing?
A... |
H: Measuring resistance in corrosion removal electrolysis
I tried to measure the resistance of my electrolysis setup (rusty object on cathode, clean iron anode, electrolyte = 3l H2O + 1tb spoon baking soda). But the resistance fluctuated from 50 to 70 kΩ even when everything was still. During the reading it would usua... |
H: Transimpedance Amplifier Not Outputting Voltage
I'm trying to build a transimpedance amplifier to convert the current from my photodiode to a voltage that can be read using an ESP32. The components I am using are:
OPA170AIDRLT Operational Amplifier (link)
QSB34CGR Onsemi Photodiode (link)
97.6kΩ Resistor
0.15uF Ca... |
H: Capacitor bursting
I attached a 0.1 uF capacitor at the input of a 5 V voltage regulator. It was rated 50 V and my input was 37 V.
After some time the capacitor burned out. I tried the same with another capacitor but it did the same. What could be the reason and how to solve it?
AI: You got fake capacitors most lik... |
H: Benefits of a differential PA in an RF power combiner design
Looking at the schematic for the Shure PA770 Antenna Combiner (found in their FCC listing) we can see the design is fairly straightforward, some amplification before combining via a typical Wilkinson divider.
What isn't immediately obvious to me is why th... |
H: What does the root locus tell us exactly?
More specifically what information can one extract from a root locus drawing without calculating the transfer function and then using Routh Hurwitz or other techniques? Essentially, what information does the Root Locus alone give us?
AI: The Root Locus shows you how the zer... |
H: Transistor Leg Orientation Question
I've ordered a PCB to be manufactured, I now need to solder some resistors and transistor to the board.
The transistor is a 2N3904 and it's place on the board is Q1. As can be seen the pins are aligned in triangular arrangement with the middle leg offset. Is this a special type ... |
H: Bias for single supply OA
simulate this circuit – Schematic created using CircuitLab
I am supplying an audio circuit with only a positive voltage of 12V. I have created a mid point (aka virtual ground, aka bias...) of VCC/2 like this in order to feed multiple OA.
Now howewer I am facing confusion on how to modify ... |
H: 10-contact FPC socket has 12 PCB terminals
I have to place an FPC socket on my PCB. I selected 0.5 pitch and 10 contacts connector. Everyone has 12 PCB terminals instead of 10.
I am confused, what are those two extra pins for?
AI: To hold the connector in place. They are "anchors", though various companies call th... |
H: Voltage regulator drop in voltage on load
1)I have been working on voltage regulators but they are not working correctly. I am using the LM7805 as the voltage regulator with 36V as input and 5V as output...It gave the 5V correctly without the load but as I added a 33ohm resistor the voltage dropped to zero...After ... |
H: LTspice 1000A simulation
I want to simulate a 1000A current flowing through a circuit in LTspice. The supply voltage is 230V AC @ 50Hz. This circuit will also have 0.05 milliohm in series with the load (this resistor acts as a shunt resistor.) The voltage drop across the resistor should be 50mV.
How do I go about s... |
H: Flyback Converter - Secondary Feedback
I am learning how to design a flyback converter power supply. I am using a reference design from TI PMP11047.
Detail schematic can be found here: https://www.ti.com/tool/PMP11047#description
I have a question on the feedback circuit. I understand that when the voltage increase... |
H: Should the sense pins be left floating on a DC-DC converter?
From this datasheet:
https://www.murata.com/products/productdata/8807040057374/uhe12-30w.pdf?1617679818000
"Note: The Sense and VOUT lines are internally connected through 10Ω resistors.
Nevertheless, if the sense function is not used for remote regulatio... |
H: Altium: Fill, Solid Region, Rectangle and Polygon Pour
Altium designer provides capability to place these objects:
I have used Polygon pour a lot and it is used to create power and ground planes. The question is about the other options. These can also be used to create a region of copper but the design rules of pl... |
H: **FINAL UPDATE** I'm getting closer to a workable circuit for this device?
FINAL UPDATE
I think the power supply is squared away accept for some caps and resistors. Thank you for sticking with me. One question:
There are two thermistors (one for each battery pack) that are used to determine charge state via batter... |
H: What is the reason some microcontrollers are designed to be powered with 5V or 3.3V while the most common battery is 3.7V?
As we know, most batteries' voltage is rated 1.5V (alkaline) and 3.7V (Li-Ion). Indeed, alkaline battery will be 1.65V when it is new, while Li-Ion can reach 4.2V when it is fully charged. Most... |
H: ESP-01 takes a long time and multiple resets to connect to Wi-Fi
I have a ESP-01 chip I'm trying to program using the Expressif C SDK. I'm using the ESP chip with a breakout board with a decoupling capacitor. I'm supplying power to it using the 3.3V pin on an Arduino Uno.
I flashed the Wi-Fi example from Expressif.... |
H: Resonant Frequency
simulate this circuit – Schematic created using CircuitLab
So, for series circuit to find resonance we have to have values of impedances (L and C) to be equal.
And then resonant frequency can be calculated wl and 1/wc but this is combination of elements how to find resonant frequency here. Is th... |
H: Derivative of a waveform
I am self studying linear circuits and I came to a very basic problem.
The problem:
$$y(t) = e^{-t} u(t)$$
where \$u(t)\$ is the step function.
Calculate the derivative of \$y(t)^{\prime}\$.
My take is:
$$ \begin{align}
y(t)^{\prime} & =\left( e^{-t} \right)^{\prime} u(t) + e^{-t} u(t)^{\pr... |
H: Molten plastic or resin over jumper terminals
I have a number of sensor boards on which I need to close two jumper connectors with solder. On the second board, my iron was not sufficiently hot and I made a mess of it. I've since replaced the iron. On the board, the solder did not adhere to the terminals and what lo... |
H: TVS diodes clamping voltage against waveform and current
Having come across these two datasheets, two patterns might be inferred:
Clamping voltage increases with current: https://www.tme.eu/Document/edf5842caa2ca49fd1e87fde0a7b9438/sts32xxxxuxxx.pdf
Clamping voltage changes significantly with waveforms: https://p... |
H: Why this equation called as a plane wave equation?
I'm confused why this equation is called as plane wave equation. Is that because the direction is constant and indicates it to propagate in only one direction?
Thanks for any comment
AI: First of all, that is not an equation, but it is a way of expressing a plane w... |
H: LED driver current consumption issue
I have an LED driver circuit that is not behaving the way I expect it to. More precisely, it’s not drawing as much current as I expect it to do. The design is not originally mine, so I don’t know the motivation behind all design choices, but I suspect the design was mostly copie... |
H: Op Amp Precision Rectifier Question
I'm struggling a bit with op amps again! I'm trying to learn how to use an inverting precision amplifier, and I'm getting very confused about the operation of the op amp in a active rectifier configuration. I'm sure it's a simple answer and I'm overcomplicating it, so here goes.
... |
H: Triridge reed relays data sheets/book? (for max current/voltage specs)
I have a 70s vintage circuit that uses a Triridge brand reed relay. It's marked with part number "220-100", and it's four pin, normally open. The operating voltage for the coil as seen in the circuit (and designed on the schematic) is 12V.
It's ... |
H: Lint tool is throwing an error about bit width when adding two 10-bit unsigned numbers and assigning to a 11-bit net
My code:
module adder(a,b,result);
input wire [9:0] a,b;
output wire [10:0] result;
assign result = a + b;
endmodule
My company recently changed policy to escalate the linting rule (W164a a... |
H: Problem evaluating the current function over a time interval in circuit with inductance
The given expression describes a piecewise function of voltage u(t) across a circuit element with respect to time and is defined over four intervals:
$$
u(t)=
\begin{cases}
V_{0} \frac{t}{(2T)} &\text{for \(0 \leq t \leq 2T)\)}\... |
H: Would this 3-phase sequence detector circuit work?
I was searching for a circuit that would detect 3 phase sequence and give dry contact output if the sequence is correct.
I have found the schematic below, from a Daikin compressor manual. I wonder if this will work if I assemble it?
As you can see all part of th... |
H: Converting AGC Schematic from Single Sided to Dual Sided Supply
I am working with the attached circuit, sourced from here: Original
This circuit is designed for a single sided power supply and has worked very well for me in the past. For a new project, I would like to use it with a dual sided power supply, providi... |
H: Why am I getting 5V at the hex inverter output?
Why am I getting 5V at point A?
The microcontroller IO is 3.3V.
AI: An open drain/collector inverter will not drive its outputs high and the pullups voltage will set Vout.
An inverter that is not open-drain will drive its outputs to near its V+ supply voltage - in thi... |
H: How does a current mirror work?
I'm trying to understand how current mirrors work.
In the text book Microelectronics by Jacob Millman, section 3-11, example 3-8, there is a picture of a current mirror:
They said if we consider \$V_{BE}\$ of these two transistors to be the same (0.7 V) then \$I_B\$ and \$I_C\$ of t... |
H: Why doesn't ESD cause a large amount of current?
It is agreed that ESD is caused by kV level large potential differences:
When we handle an ESD sensitive device such as a MOSFET or a type of diode etc., why doesn't it burn when it gets damaged by the ESD? If V = I * Z , wouldn't kV level of voltage cause a huge cu... |
H: PNP transistor symbols, pins and footprints
I am currently building a soft latch circuit in a CAD editor.
I want to use a PNP transistor, and have 2 choices for this component.
However, I am confused when comparing the datasheets of the components with the symbols and footprints in the CAD editor.
Part 1 looks like... |
H: Good book on EMC and EMI
I'm looking for a good book about EMC and EMI.
There are plenty of books talking about norms and standards, but I'm looking for a book focusing on understanding the logic and physics behind it. And how to design filters and housings to reduce EMC and EMI issues.
Thanks.
AI: Fast Circuit Boa... |
H: Current regulation compensation SG3524 and right place to place sense resistor
What is the right place to place current sense resistor? As in picture we get traingular wave n position 1, sine wave with highest amplitude on pos 2, smaller sine wave on pos 3 and nearly flat line but still there is sine wave on pos 4.... |
H: Please explain the highlighted part on the working of a D flip-flop
The section of the textbook Digital Design by Morris M. Mano and Michael D. Ciletti says the following about D flip-flops:
Another construction of an edge-triggered D flip-flop uses three SR latches as shown in Fig. 5.10. Two latches respond to th... |
H: Altium: Comment field of schematic symbols
Eagle does not contain a Value field for the schematic symbols. Rather, it contains a comment field. From what I know this field shall contain the resistance, capacitance and inductance value for resistor, capacitor and inductor component respectively. In these cases, the ... |
H: Does a MOSFET require a gate inline or pull up/down resistor when being driven from a NE555
I am trying to run some indicators/flashers on my own made bicycle. I have attempted ready-made automotive flashers but have found the lights don't draw enough current for the 2-wire ones and get weird behaviour. With the 3-... |
H: Second PCIe on KeyE M.2?
Based on this online resource, KeyE M.2 has
2x PCIe x1 / USB 2.0 / I2C / SDIO /
UART / PCM
Their pinout table shows these lanes (for E-key):
35 PETp0
37 PETn0
41 PERp0
43 PERn0
47 REFCLKp0
49 REFCLKn0
50 SUSCLK
52 PERST0
53 CLKREQ0
55 PEWAKE0
59 Reserved/PETp1
61 Reserved/PETn1
65 Reserve... |
H: How can I change the frequency of a sine wave from 5 MHz to several smaller ones, e.g. 1kHz, 100Hz and 1Hz?
5 MHz is the frequency of the quartz based oscillator. I get a clean, sine wave output. I would like to (divide) this signal into several, lower frequencies in steps, e.g. 1kHz, 100Hz and 1Hz. I don't want to... |
H: I am trying to figure out why npn does not work here... what assumptions should be made?
So I tried the calculation of
ic = (15-10)/2k = 2.5mA -> ib = 25uA, ie = 2.525mA
Vce = 15 - 2k*(2.5mA+2.525mA) = 4.95V
As Vbe = 0.5V, Vb = 5.55V required
voltage drop by 10k resistor = 250mV -> Vop,output = 5.8V
and I'm stuc... |
H: Missing indicator in XL4016 buck converter module
I’ve bought below XL4016e1 buck module. There is an empty spot between the Indicator light and Input negative, between the left most capacitors.
What component is missing there? an LED/buzzer/adjustment POT?
What it supposed to do/indicate? Short circuit, No load, ... |
H: Running multiple ICs with a single crystal
I need to run three AD7779 ADCs using the same clock signal for synchronization. I don't have access to an oscillator which I can use as a master clock, so I was wondering how I could use a single passive crystal to run all three ICs.
AI: The ADC you describe supports the ... |
H: How to achieve the lowest noise configuration from a differential setup
I want to be able to capture a differential output from a shunt resistor. The shunt resistor differential voltage will range from 2.5mV to 50mV at 50Hz.
My initial idea was to send this signal through a unity gain differential amplifier and the... |
H: Parasitic oscillations for phase shift not equal to -180 degrees
From "Learning the Art of Electronics" by T. Hayes and P. Horowitz, Cambridge University Press (p. 360):
As per above figure, the LF411 op-amp imposes a -90 degree phase shift on output voltage. It is stated that to prevent parasitic oscillations, we ... |
H: L298N as LiPo charger
The L298N motor driver contains a voltage regulator (lm317), so is it possible to adjust the output voltage beyond 5V and 12V to charge a 7.4V lithium polymer battery?
AI: That's an extremely bad idea. Even if the chip contained a voltage regulator like the LM317 (which it doesn't, BTW, see be... |
H: NCP1654 current Mirror
Regarding the NCP1654, there is a circuit in the IC block diagram that I don't fully understand. Could you please take a look at the figure below and help me understand the blue and red lines?
below are my questions,
Is the blue line also referred to as the current mirror?
If both circuits... |
H: Why am I getting clipping at the inputs and outputs?
I have designed the below circuit in LTspice. This is used to measure the voltage drop across the shunt. I know people on this platform have said I should use a current transformer, but they are not that accurate.
Simulation results:
Can someone explain to me... |
H: Laplace analysis of an unstable multivibrator based on an op-amp
I have tried to do a Laplace analysis of the following astable multivibrator circuit:
simulate this circuit – Schematic created using CircuitLab
I understand the principle of working. and although the component values were somewhat arbitratry, the ci... |
H: Combining a mono signal with a stereo signal
I'm creating a stage sound system
I have already created a preamp for the microphone and led the connector through which I will feed the music. Now I need to mix music with a preamp. The problem is that the preamp works in mono and wants to keep the music in stereo.
I wa... |
H: How to measure table saw torque and horsepower?
I have a table saw that has the following rating:
120V at 60Hz
standard 5/8" arbor
I took the following measurements to see how they compared with the advertised specs. The below are the actual numbers measured.
RPM: 4,850.4
No load amp draw: 8.7A
No load voltage (ta... |
H: Switching line between 5 V and ground using a 3.3 V signal
I am working with a PCB which looks like shown below. Switching the central line between 5 V and ground toggles the LEDs.
I had this PCB connected to a 5 V Arduino dev board where the switch line was connected to one of the GPIO pins; switching between hig... |
H: High power DC to AC inverters
I've looked around and found quite a few DC to AC inverter circuits; 12-24 V DC input and 120-240 V AC output.
None of them can support more than 400 W though, and they all use at least one big transformer. How do commercial inverters output enough power to drive up to 3500 W and still... |
H: LT1389-5 voltage reference output is not as expected
I am using the LT1389-5 for one of my projects. My circuit is given below.
For 5 V output the maximum operating current is 10 mA. This is obtained from the maximum ratings.
I calculated the value of R1 based on a total current of 15 mA.
R1 = (12-5)/15 mA = 466 Ω.... |
H: I'm trying to make a Zeta converter
I tried to design Zeta converter to be used in an MPPT charge controller.
VIN: 10-22 V
IIN: 3 A
Fs: 30 kHz
I have a problem.
With my design, the voltage is not coming out so well and nothing changes if I change the duty cycle (in real, not simulation, I have made a prototype.)
... |
H: ATMega32U4 USB design considerations
I'm desigining a board with ATMega32U4 microcontroller.
The board will be minimal, and will feed the microcontroller from USB of an M.2 socket (E type) on a PC mainboard:
Now, checking Leonardo's schematic, they are using varistors to protect USB's D+ and D- pins:
This is perf... |
H: What are the possible implementations of LUT on silicon?
I'm looking for the possible ways to implement a LUT. The only way I know is to use Flip Flops to store the outputs and a MUX to select the output using the input as a select signal. Is there any other way to implement it?
AI: One alternative method to make a... |
H: What does this diagram with two opposing arrows depict?
I have an astronomical timer relay that controls lights. Its user manual shows this diagram:
What do the opposing fat arrows (vertically aligned) indicate? How would one read them? Also, it seems like there are three switches to the far right (within the l... |
H: Need a way to decrease the current used by a stepper motor through a TMC2209 when it is idle
I am using an ESP8266 to control a stepper motor through TMC2209. In my use-case, the motor is idle 80% of the time. But i can't turn off the enable pin since i need the motor to still be fixed in its position. Is there a w... |
H: Is the emitter-base diode forward biased when an NPN transistor is used as an amplifier?
I came across a question asking about the state of both the emitter-base \$EB\$ and collector-base \$CB\$ diodes when an NPN transistor is used in amplification.
My understanding is that for amplification to happen, the \$EB\$ ... |
H: Tesla coil music
I want my solid state Tesla coil to play music. I built it to only accept square wave input. Does anyone know howI take a normal melody (no voice,) only keep the main soundtrack (no bass or anything else) and convert it into pure and simple square wave?
AI: The task you are after is easier to appro... |
H: Amplification of the oscillation of a signal without amplifying the offset
Knowing that I only have op-amps, comparators, resistors, capacitors, and simple diodes at my disposal, is there a simple way to amplify the small oscillation of such a signal without amplifying the mean of the oscillation? (I would like the... |
H: Is debouncing necessary for a power switch?
A few months ago I asked for help designing a circuit for powering on a microcontroller using a tact switch, and I finally just prototyped the circuit that @Jonathan-S. suggested. It works great. However, I neglected to consider any effects of contact bounce in the tact ... |
H: Op-amp high-pass filter and low open-loop gain at higher frequencies
How can a high-pass filter work when the open-loop gain of an op-amp completely attenuates from a certain frequency?
I understand that the open-loop gain of an op-amp is what limits every closed-loop gain. So if a high-pass filter is a closed-loop... |
H: How do reduce switching randomness from comparator without comprimising switching speed?
I'm working on a coil gun project and I've discovered an annoying problem involving a voltage comparator output which has lots of noise/ rapidly switching high and low before coming stable. Here's the circuit:
D4 projects light... |
H: Why is the output of this class AB amplifier not equal to Vsine?
I'm simulating a class AB power amplifier.
According to the theory that I learned, the voltage at C8(2) should be equal to C10(1.) Why is there a huge gap between them (5.83 vs 1.89?)
The input impedance of this circuit is an approximation with R10 = ... |
H: Boost converter: using smaller inductance than "typical" application?
I need to boost 3.3V all the way up to 12.0V.
Current requirements are rather small, I only need to power an SSD1309 OLED driver (from pg7):
Common maximum sink current: 40mA
Almost all of the available high-quality boost converters are providi... |
H: Filter phase shift and causality
A filter I have is showing to have a positive phase shift of ~30° at 1 kHz:
Also, it seems that the output signal is actually advanced by 30°.
But we all know that this is impossible because of causality. So what's really happening here, and how much degrees of phase shift should... |
H: Total impedance in a circuit
To determine the current I have to calculate the total impedance, here named \$Z_{Ges}\$, in the circuit which can be seen in the first picture.
First I summed \$R_1 \$, \$C \$ and \$R_2 \$ as a parallel impedance \$Z_{1C2} = (Z_{R_1} || Z_C) || Z_{R_2} = (\frac{R_1 * \frac{1}{j\omega ... |
H: Change in switching frequency across gate source
I am working on a bidirectional half bridge DC-DC converter. The converter circuit is shown below.
I used a TLP250 IC for the driver circuit. A square wave with 20 kHz switching frequency was given as input to the driver circuit. The output from TLP250 is a square w... |
H: Crystal oscillator construction
I am not sure about how the crystal oscillators are made. Some say it has a crystal but some says it has an LC combination which requires a parallel capacitor to resonate with the internal LC combination.What is the actual construction.
AI: A crystal oscillator has two things : the o... |
H: How can I solve these two equations to determine resonant capacitors for a wireless charging coil?
My questions:
What are S, D, and the apostrophe above Inductance?
Is the equation looking for the inductance of the coil or the circuit?
Once I know what S and D stand for how can I determine their frequencies?
The ... |
H: Placing feedback loop parts on PCB
I have one PCB for control circuitry and another for power parts (input caps, transformer, full bridge, output caps...).
I would like to ask if I can place some feedback parts (red square at picture) directly on "power board". Why I wanna do that? Since 10k resistor provides DC of... |
H: Verilog - Unexpected behaviour on first clock cycle
I've done a bit of experimenting with Verilog recently, and I ran into a problem where it doesn't behave as I'd expect. In one of my modules, I have code like the following that is designed to simply track odd/even cycles, because I'm performing operations that ta... |
H: What do the letters mean on this LiPo (or Li Ion) battery?
I’m trying to find a replacement battery for my Bluetooth earphone as they drain out very fast. It is a 3.7 V 55 mAh.
Looking through the options I see batteries with better capacity but the letters are different (the battery I have says AUN others have wri... |
H: MCP2515 and Crystal Error
I'm making a board with MCP2515T-I/ML due to space constraints and it won't start up.
(datasheet) https://ww1.microchip.com/downloads/en/DeviceDoc/MCP2515-Stand-Alone-CAN-Controller-with-SPI-20001801J.pdf
This is the pcb layout and schematic.
The top layer copper pour is 3.3V and the seco... |
H: Multiple feedback design methodology
I am having trouble finding a step by step approach to the MFB filter. I came across a tutorial from Analog Devices but I am struggling to find what is the reasoning behind their equations, and can't find any references about it. Their design goes as this:
Now I understand the... |
H: Is it safe to run an instant power supply (IPS) with a flooded lead acid tubular battery (12V, 100 AH) in a small flat/apartment?
I live in a place where blackouts and power outages occur every hour. For backup power for two lights and two ceiling fans, I want to buy an IPS that runs on a flooded tubular acid batt... |
H: What is the purpose of chaining series of NOT gates?
I have seen these a few times, but I don't know what the purpose is. Clearly the purpose is something else than just to invert the signal. Otherwise just one or two would be enough for that. Also, does this configuration have a name?
simulate this circuit – Sche... |
H: Interconnecting two PCBs whose approximate distance is 2mm
I wish to design two separate PCBs (due to mechanical requirements), with 4 interconnections in between them.
Now, I could use standard pin header males and females for this task:
However, PCBs distance is less than 2mm (!).
I couldn't find shorter pin hea... |
H: Why does a walkie talkie have TS for audio output and TRS for audio input?
Why does a walkie talkie have TS for audio output and TRS for audio input?
Is there any sense to have stereo for microphone and mono for speaker?
Why doesn't the manufacturer use TS for both audio input/output?
Please see walkie talkie audio... |
H: Can I do AC analysis of a transistor solely using the input/output impedances provided by the datasheet?
I learned to do AC small signal analysis of a BJT transistor with dV/dI ~ re = 26mV/Ie. But I don't understand why we take Vbe as 26mV here. Also, in the datasheets, I found graphs of input/output impedances for... |
H: Capacitance for which the ratio of the input and output voltage is independent from the frequency
I have the following circuit with resistors and capacitors in parallel (see Picture 1):
I have to determine the capacitance \$ C_1 \$ in such way that \$\frac{u_e}{u_a} = 1 + \frac{Z_1}{Z_2} \$ is not dependent on the... |
H: Shall I connect '-' terminal of power supply to earth GND (green terminal)?
Attached is the current lab setup for my chip testing. The green square represents the main PCB board, and little blue square represents the chip. The chip needs separate VDD voltage for its analog and digital circuits, but their ground is... |
H: Replacing 4pin USB with USB-C works only in one direction
I have an AR1100 with a usb mini-B female connector :
https://github.com/adafruit/Adafruit-AR1100-Resistive-Touch-Controller-PCB
Basically 4 usual USB pins : GND, D+, D-, +5V
I want to replace it with a usb-c connector.
At first I put a pull-down 5.1K resist... |
H: What is the rotatable switch used in smartwatches called?
Some smartwatches such as an apple watch and Samsung Gear use a rotatable switch for navigation that make a clicking sound when turned. The companies call it "crown" (some details - pdf). I'm trying to replicate the same for my arm computer more or less. I c... |
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