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H: Why don't we use decoupling capacitors for open-drain outputs?
If an IC with open-drain outputs (and hence pull-up resistors) is used, we of course put decoupling capacitors on the IC supply, but why don't we also add decoupling capacitors between the power pin of each pull-up and ground?
When an output switches hi... |
H: How to fix ERC error for power pins
I'm working on a board in KiCad that is supplied with 12V regulated power which comes from a terminal block (1725753) and then it's routed to a DRV8871 DC motor driver's supply pin. Now the ERC flags this with "Error: Input Power pin not driven by any Output Power pins" because I... |
H: What are the tradeoffs between NPN vs PNP power transistors?
I'm working on a linear power supply design leveraging the uA723 regulator and I need power transistors to meet the current requirements (~2-3A). When looking looking through the regulators datasheet, they provide examples (see figures 4 and 5) for extern... |
H: 6 to 0 count down timer
I'm making a 60 second timer. I already made the 1st digit in my previous question. I want it to start at 6 not 0, basically 6,5,4,3,2,1,0. I made the flipflop state table and followed the similar process I used in the first digit.
But when simulating it, it starts at 0,7,6.... I want it to... |
H: ESP32 VSPI/HSPI SPI channels only support 3 slave devices?
From what I understand there are two methods for multi-subnode SPI - Regular Method and Daisy Chain Mode [1]. In the regular method, each slave device is designated a separate CS (chip select) pin on the master device which is driven low when the master wan... |
H: Power amplifier vs voltage amplifier
I am trying to learn more about the different types of amplifiers.
I have built a voltage amplifier but I am trying to learn how to build a power amplifier and I don't understand the design differences between them.
When I try to look up a class A power amp and a class A voltage... |
H: Nodal analysis doubt
Can we apply nodal analysis to find out the current in each branch for this circuit:
I am having trouble to find the correct reference point where I can take V = 0.
(If you are down voting the question, please mention the reason.)
AI: Explicitly done based on comments: I have swapped the eleme... |
H: DSP system step response
I am preparing for my DSP exam and have this question about block diagram of DSP system: "Fsampling = 16 kHz, Delay = 4000 samples, Gain = 0.75. Provide impulse response of this system:"
I assume that this is FIR filter, so impulse response would be finite. I tried drawing impulse response... |
H: PIC assembler to perform arithmetic on 10-bit number spanning 2 registers
I wondered if there was any 'clever' way of decrementing a 10-bit value which is stored across 2 registers. In this case, its the PWM duty cycle value which has its 8 MSB in PWM1DCH and its 2 LSB in PWM1DCL (in bit positions 6 and 7).
I've f... |
H: With what can I replace a MLCC capacitor to ground of 6.3V and 4.7uf
I have a mobo and the cap highlighted above in the picture C4 (6,3V 4,7uF) has broken off, I want to know what can I replace it with if I dont have specifically the same voltage and capacitance but the same dimensions 0805. The mobo is h61mxv v2.... |
H: Does a ATTINY88 Micro Arduino clone have a quartz crystal? (LaserTag project)
Is the square thingy under the Reset switch (on the right side) a quartz crystal?
I have found this board crazy cheap (1 euro) compared with a real Arduino Nano.
I need to generate a 36kHz signal, so it needs a quartz.
AI: It surely looks... |
H: How to prevent photoresistor sensor from draining battery
I'm looking for a simple hack to minimise current when detecting change in light intensity using photoresistor.
I'm using ATTiny85 in deep sleep (power down, ADC disabled, using below 1 microamp) waking by pin change (interrupt pin). After pin change ATTiny ... |
H: Noninverting input voltage seen on V+ pin of OpAmp
I've built this exact circuit here, except for one variation: SHDN is connected via a 10K resistor to ground. The opamp should be off!!!
What happens is when I connect a battery (or power supply) to VBAT, somehow that voltage is makes it way to the V+ pin, which is... |
H: Single Ended to Differential Conversion with Opamp and Correct DC Biasing Method
First schematic below is the initial gain stage of the intermediate signal generated by mixer of radar. It is passed through sallen key high pass filter.
Second schematic for differential to single ended conversion with some gain. And... |
H: Time function for an equivalent circuit
In the IEEE magazine 6. NO. 3. JULY 1991 A Novel Soft-Switching Full-Bridge DC/DC Converter: Analysis, Design Considerations, and Experimental Results at 1.5 kW, 1OOkHz the following converter has the active state when any of the pair of transistors S1-S4 and S2-S3 are on.
... |
H: Using UART/USB Bridge vs straight USB stm32
I've been doing some research over the last few days into implementing usb communication protocol on the stm32. I know that the stm32 has dedicated pins for USB communication, however I still see a lot of designs using a UART-USB bridge despite the existence of these pins... |
H: Adding on and off state in a 555 timer clock circuit
I'm making a clock signal for my circuits, and I'm utilizing the 555 timer for this. I made this circuit below which outputs a clock signal. And now I'm trying to figure out how can I add on and off state on it.
I want the clock turn on when a constant high input... |
H: PSPICE non sinking voltage source
In an ideal world, most power supplies have a current sourcing feature but not a sinking feature. In this circuit, you can see that the 15V supply is sinking current. How can I prevent this in Pspice?
AI: There's a clue in the 72.73 μA flowing into R2 (330 kΩ): -
That current and ... |
H: Arduino Nano in PCB for a controlled heating rig - Can't get it to work
Background
I'm making a heat sealing machine. The mechanical side is all OK but the electronics is challenging me. Here's the gist of the setup. I've put it all in the image below. Apologies for the rather unconventional circuit diagram...
The... |
H: Leakage inductance in a series resonant converter
I know that the leakage inductance is present due to the imperfect linking of flux between the two transformer windings. I have selected a core for the transformer to be used within a series resonant converter.
Using FEMM, I have simulated the transformer core along... |
H: Maximum voltage applied to the BJT base
I have a functional circuit designed for return line reverse protection, and a relevant portion of the circuit is shown below:
simulate this circuit – Schematic created using CircuitLab
In this circuit, I anticipate that when +28V is connected to the return line, it will tur... |
H: Inductors - understanding the depth of its working
When there is an initial change in current, I understand that the inductor resists the change. but how does it eventually give in with the flow of current?
can someone give me the nuances of the working of the inductor?
AI: The inductor acts against a change in cur... |
H: How to limit current for this LED in circuit with a load?
I'm a newbie in electronics and just recently decided to get some deeper knowledge and try to start some projects. But it didn't take that long before I became stuck. Here's my problem.
I want to design a circuit with 12DC output that will be connected to tw... |
H: Hold button for UK Landline telephone
We have retro rotary telephones, and I'd like to make a hold button for the one in my office in the UK.
This is literally a "ye olde rotary phone" (1940s) made from bakelite
I have fairly basic electronics skills but I don't actually know how the phone works, in that sense anyw... |
H: Calculate the output IP3 of this transmitter
The following is a tutorial question from my teacher.
A transmitter requires the IM3 products to be -65dB below the main tones when the total output power is 20 dBm. Calculate the output IP3 of this transmitter.
This is what I think.
The output IP3 is the third-order ... |
H: 5V to 3.3V LD1117 voltage regulator design
I am using two 5V 1W voltage sources in parallel and I want to regulate the output to 3.3V using an LD1117. I need help calculating the R2 value for the LD1117.
I have read the datasheet linked below but I find it confusing. How do I calculate the value for R2, given that ... |
H: How can we know reason \$9.6[dB]\$ from this graph?
The diagram can be found at graph link
A lot of textbook give this formula.
$$IP3 = P_{1dB} [dBm] + 9.6[dB]$$
This equation is valid for both input and output referred quantities.
But how can we know reason \$9.6[dB]\$ from this graph?
AI: But how can we know rea... |
H: Dual channel control using a single switch
I have a circuit that uses an EMG module that requires a V+, GND and V- input. When only one of these lines are turned off, the module remains on.
simulate this circuit – Schematic created using CircuitLab
I need to be able to open and close any two lines with a single sw... |
H: Ground fault detection on an ROV
I'm helping my friend's kid with a school project where their team has to produce a small ROV. Most of their design I was able to review and help make corrections with them but I'm stumped at one junction, because it's not something I've had to work with much... Ground Faulting. The... |
H: What is the exact function of this device connected between ground and neutral?
This is the photo of the power distribution panel inside industrial building. On the left most, next to the two thick wires colored yellow/green so as it is likely to be the "ground" we see a strange looking device connected between the... |
H: Is an RF sampler a good way to protect my network analyzer during high voltage impedance measurements?
When I characterise ultrasound transducers, I normally do it with a network analyzer in a shunt configuration - ie, I connect the transducer across port 1 of the network analyzer. This gives me plots of phase and ... |
H: How can I enter boot mode with an STM32F411CEU6?
I ordered a PCB with the following schematic based on an STM32F411. As you can see, the NSRT pin is connected to a LP filter. I think I should have connected it to a switch to easily enter boot mode, but I still have 6 external pins: GND, +3V3, SWDIO, SWO, SWCLK, and... |
H: Is it worth adding a transistor on shift register output to drive a LED?
I want to light some LEDs (from 1 to 5 at the same time) using a shift register. I read that the shift register is supposed to output 6mA per pin: ±6-mA output drive at 5 V, which seems a bit low so I figured I could use transistors like descr... |
H: Is it wise to determine heating element temperature from resistivity?
Context
I'm making an electric furnace for melting metal, and aiming to make my own controller.
Everyone seems to just use thermocouples and a control loop, I thought perhaps I could just measure the resistivity from the heating element.
I'm plan... |
H: Is this the correct isolated circuit to control a relay output from a Raspberry Pi GPIO?
I am making a circuit for an optically isolated relay output controlled by a Raspberry Pi GPIO pin.
I am not sure if this is the correct way of doing it. Can someone please help me out on this?
Edit: Modified circuit based on... |
H: Is resistor needed for Flash IC?
I am making my first micro controller board with the rp2040. It requires external flash and so I picked the MT25QL128ABA1EW7 since it seems to match all the requirements based on this document: https://datasheets.raspberrypi.com/rp2040/hardware-design-with-rp2040.pdf#_supported_flas... |
H: Is there concept called dual ethernet?
I came across a word called dual ethernet while working on a project and it got me curious like is the word misspelled or is there any real concept on this?
AI: 'Dual ethernet' may well be referring to bonded ethernet.
This is where two physical ethernet cable connections are ... |
H: How can I utilize PSpice for ESD simulation?
Issue: I do not know how to build a ESD simulation model in PSpice Orcad capture.
Question: What is wrong with the simulation circuit? The simulation result seems like the ESD is not discharging properly. Why I cannot see the same response as the simulation result in the... |
H: Square wave of oscilloscope for RC circuit
I have some ceramic capacitors and would like to know for sure what capacitance they have.
I don't have a multimeter (or any other instrument) that allows me to measure capacitance directly, so I build a simple RC filter that filters a square wave input, I know that the vo... |
H: Can I use thicker wires or twisted pair for Ethernet?
I'm planning to use 2 types of connectors:
A : GND + 24V + 100Mbps ethernet (4 wires) + 2 wires with various functions
B : 1 Gbps ethernet with PoE (8 wires)
For type B, I found of the shelf connectors meeting my needs (small size + subssea,) but I haven't fou... |
H: Charging li-ion 72V with solar MPPT controller
I have an EV 72V li-ion battery with given charger (peaks at 11 A).
My MPPT solar charger is designed among other types for li-ion up to 96V ie 12/24/36/48/60/72/84/96V settable at 72 V. 50 A max.
Given the amps will vary depending on sunshine it will provide the corre... |
H: Electrician Theory: Delta Star Induction motor question
This is the question I am trying to solve:
A delta connected fully loaded induction motor draws 90A from a 400V supply when started direct online. Show by calculation the current at start up that the motor would draw when connected to a star delta starter in ... |
H: Op-amp schematic connection questions and DC biasing
In the first stage the signal is converted to single-ended, and it is amplified using a digital potentiometer in the second stage to be able to change the gain with a microcontroller.
In the last stage I have converted the signal back to differential again.
Thd A... |
H: Screw post or binding post on PCB for lugged gnd wire?
I need to attach these four wires to a PCB I am designing.
The three ferruled wires will be connected through a terminal block. I have space next to the terminal block for the lug but I need a method for connecting the lug to the PCB.
A simple solution is just ... |
H: Differential amplifier op-amp schematic connection and DC biasing
I have a differential IF (intermediate frequency) signal generated by an ADL5801 RF mixer.
Stage 1: the signal is amplified before active filtering and it has LC LPF in the beginning for filtering unwanted frequencies above 2 MHz.
Stage 2: the signal... |
H: Undervolting magnetically held switches
I have acquired a Honeywell ET series switch (best datasheet I could find) whose holding coil is rated to run on 28 VDC. I know it is often deployed in aeronautical environments where voltage can drop to near 24 V when operating on battery.
From my testing, the switch seems t... |
H: What is the function of CCM1 and CCM2 in this resistive bridge measurement circuit?
The circuit below can be found on page 59 of the ADS122C04 chip datasheet. The purpose is to take the differential input of two voltages from a resistive bridge. For example, I am using it to collect data from a load cell. I underst... |
H: Is it safe to remove this LED from that motherboard?
So, I've bought this SATA case from internet but it has a really bright light on it and annoys me. I don't haver any kind of tool to manage any electronic component, and neither have electrical tape to hide this light, so I would like to know if it is safe and it... |
H: Positionally aware 360° (or beyond) motor (DC or stepper)?
Most servo motors out there are driven within 180° (at least hobby ones). There are more bulky and expensive servos out there as well. Since, I have tight space constraints, I am looking for a solution to have full positional awareness (0-360°), an can even... |
H: Simple TTL: Is there a way to "detect" a high-z state and easily use that to drive other logic?
I have two TTL style logic chips, call them A and B (*), where the outputs of A are the inputs to B (think: 8 data lines). A has tri-state outputs, so when they are turned off they float. B is an inverting buffer which a... |
H: Gate driver selection for digitally controlled via PFM, LLC resonant half bridge charger
I am designing a LLC half bridge charger. I am going to use a microcontroller to control the switching frequency, with feedback from the output to smoothly control the switching requency.
I don't understand how can I control th... |
H: Why do the metal sticks (for the ground) on the ground plane antenna reflect and not absorb?
From my current knowledge, any metal whether grounded (and or earthed) or not will reflect radio waves as seen on dishes, Faraday cages, etc. On the other side the ground in transmission lines or the ground planes in PCB, I... |
H: Can you detect when an incrementing counter has reached N by AND'ing the expected set bits?
With a incrementing counter, starting from zero, I can tell when 128 is reached by looking for a positive edge on bit:7.
I can detect when 129 is reached by looking for a positive edge on (bit:7 & bit:0)
I think that I can d... |
H: Differential output resistance with LTSpice
I have a simple NMOS FET where I would like to plot the differential output resistance at the operating point of Vgs = 1.7V (which is the Vgs voltage for Id=9.4mA)
I managed to plot the output resistance with the help of the behavioural source B1 as follows:
I can read f... |
H: Voltage divider for symmetrical DC power
Let's imagine there is a symmetrical DC power supply +10V and -10V and two resistors, R1=10k and R2=100k. What is the voltage in point A? What is the correct formula for this kind of calculation?
AI: The voltage between two points is called a potential difference. In most c... |
H: Is it safe to connect a µUSB bus to another voltage bus?
If I connect my µUSB bus to the other 5V bus what are the consequences?
What can I put in place to make it safe?
The µUSB would be plugged in while the circuit is active to reach a µC by default.
The other two states are that 5V will be off and 5V will not p... |
H: DC/DC step-down converters: what trade-offs prevent lower minimal input voltages?
I'm currently looking into isolated step-down DC/DC converters, to convert from high voltages (a few hundreds volts) to 24 V.
I'm surprised that the minimum input voltage is often quite high (like 200 V for a 300 V nominal input volta... |
H: Connecting 25MHz crystal to STM32H7
I want to connect a 25MHz crystal to STM32H750. However, I've trouble finding a part which is suitable for use with this particular MCU.
From AN2867:
In addition:
The gm for STM32H750 is 1.5 mA/V (datasheet). This means that in order to meet the recommendation, the crystal has ... |
H: Usability of COB LED filaments as replacement for traditional filaments
COB LED filament household lightbulbs are a thing now. Can someone explain to me what limitations there are to using these COB filaments in car headlights? They emit a very similar light pattern if you preserve the geometry and glass shape. I b... |
H: IPC 7251 annular ring meaning
When looking at IPC-7251 Table 3-3 (see the table in Sergei Gorbikov's answer at How to determine annular ring width for thru-hole pads?), for a through-hole pad in Level B the annular ring is given as 0.35mm. Is that the actual annular ring width or the total width to add to the hole ... |
H: Alternative to pull-up resistor
I am building this AND gate, and I managed to get it to work properly. However, I had to increase the value of the pull-up resistor to 3 megohms which is too big for what I need. However if I don't make this value big enough, when my input is (0, 0) for example, I won't get an output... |
H: Using an op-amp to produce a low-current voltage rail
I'm working on a CubeSat project and I need to produce a 3.3 V voltage rail for an ADC (ADC128S102). The ADC only needs 3 mA total when in active mode. I'm selectively upgrading the most critical parts on the bus to versions that are radiation tolerant/hardened.... |
H: How can there be no Thévenin voltage with only a dependent voltage source?
I don't understand why the Thévenin equivalent is equal to zero in this case because, if the load is a resistance, then yes, the circuit would be dead as there would be no voltage drop across Vx. But if there is a voltage or current source i... |
H: How do P-type transistors conduct current?
Going through a Introduction to Computing Systems by Yale N. Patt and Sanjay J. Patel and currently reading a chapter on MOS transistors. From what I understand, N-type transistors "close" a circuit when supplied with current and break it if absent. P-type transistors act ... |
H: Is this relay circuit valid?
This is my current circuit draft
Which had the SPST-NO symbol adapted from the supplier's symbol
I have not chosen any specific parts for diode, resistor or transistor.
ALDP105W Relay datasheet: here
I am new to circuitry and PCB design, I was wondering if anyone could help me:
Sp... |
H: NAND-based bistable with momentary switch
I want to create a circuit that has two outputs, and two states, where the outputs are either "on, off" or "off, on". The state should be switchable using a momentary SPST switch.
I am using two inverters from a CD40106.
Here is the current circuit:
Here, VCC is 9V (the c... |
H: Avoiding overshoot in step response for robustness
In Systematic Design of Analog CMOS Circuits (Jespsers, Murmann) page 343, the following is stated in the context of where to place the non-dominant pole in a second-order loop transfer function of a switched-capacitor amplifier:
The case of ωp2/ωu1 = 4 (Q = 0.5) ... |
H: LTspice: simulating temperature
I want to simulate the effect of temperature on a semiconductor.
I can use .temp ... or .option temp ... or .step temp ..., but all of these show multiple lines and I am not able to do anything with it in the simulation, for instance, having an op-amp/comparator react on the change i... |
H: How much power to drive this actuator?
I have a linear actuator that I need to design a circuit for, where an Arduino is going to control it.
Here's the datasheet (pdf) for the actuator: https://www.red-magnetics.com/en/product-groups/linear-solenoids/cylinder-solenoids/its-lz-2560-z/?pdf=1
It's the first time I'm ... |
H: How do I configure a negative clamper in LTspice?
I am trying to make a negative clamper in LTspice. The pulse source goes from 10V to -10V harmonically. My aim is to lower it's voltage by 7.3V, so it will have a pulse graph going from 2.7 to -17.3V, but I don't know how to configure the circuit for that.
AI: My ai... |
H: Why don't the C1 and C2 capacitors discharge?
In the circuit, we know that when D1 is connected then the C1 capacitor is also in the circuit until it's fully charged. Why when D1 is disconnected and D2 and C2 are in the circuit, C1 can't discharge? What is the reason behind it? And so doesn't C2?
AI: In the circui... |
H: Bizarre behavior with SIN LTSpice
I have this circuit I'm supposed to analyze. I am asked to set v1 to a sine wave V1= A sin (2pi f t) with a frequency f = 1 kHz and A = 5mV. I think I did everything right, but when I run the simulation I have 2 issues:
Edit: I just realized that it should be SIN(0 0.005 1k), but i... |
H: Where am I wrong in understanding feedback network?
The following is from the book Design of Analog CMOS Integrated Circuit, Page 314.
Calculate the open-loop and closed-loop gains of the circuit shown in Fig. 8.66(a). Assume that λ = γ = 0.
For feedback network
consisting of \$R_S\$ and \$R_F\$,
$$h_{21} = -\frac... |
H: Is there a component that can record circuit on-time without a battery?
I don't know if such a thing exists already. I'm looking for a component that can record how long a circuit has been powered on. Kind of like the "change filter" light on a fancy vacuum cleaner. It must be able to resume recording after being p... |
H: Trying to design a synchronous sequential counter circuit with a given sequence
I'm trying to design a counter circuit that counts 6 → 4 → 2 → 0 →
2 → 5 → 3 → 1 using T flip flops and I haven't been able to achieve it. I tried the steps below and designed the circuit below in CircuitVerse, but it doesn't work prope... |
H: Testing wheelchair motors on an AC to DC power supply
I recently purchased 2 Jazzy Wheelchair Gearbox Motors (12-24 VDC) to use in a robotics project. I've done tons of LED, Arduino, and smaller motor projects but this is my first time doing a project with heavier duty electronics so I want to make sure I don't bu... |
H: How to improve my son's solar bobble head
My son has a minecraft solar bobble head (in this case a bobble Steve). Under light it swings a diamond sword this exact one (Puckator Officially Licensed Minecraft Steve Solar Pal https://amzn.eu/d/gH1XvAn).
It is made up of a small solar cell, connected to a circuit board... |
H: When should you use default operators vs. implementing your own hardware?
When using Verilog, when should you use default operators like a + b, and when should you implement your own version of the hardware, like writing a full adder? Is it only when you need a specific need, or is it better practice to know exactl... |
H: Help with N-Channel MOSFET circuit and behaviour
I have a bare PCB with N-Channel MOSFET in the input (12V), however when connecting the power source, no voltage comes out from the MOSFET, and when connecting with reverse polarity, the output from the MOSFET is -12V.
Tried three different MOSFETs, all give the same... |
H: Is this behavior for a Murata PIR motion sensor test circuit expected?
I am using a Murata IRA-S500ST01A01 PIR motion sensor. This is the datasheet. Based on a description of the pyro-electric effect from part 2 of these application notes for the IRA S210 (same family of sensors), the output voltage of the sensor s... |
H: Neutral to ground bonding place question
Does the neutral-ground bonding need to be done before the RCD/GFCI breaker? If there is an energized metal frame due to a fault, will the RCD/GFCI breaker see a difference between live and neutral only if the bonding is done before the breaker?
AI: Maybe this is a very stup... |
H: Help demonstrating mathematically the behaviour of a passive filter
Consider the following circuit:
By inspection, it can be said that the complex impedance of the circuit will be \$R_2\$ for very low frequencies and \$R_1\$ for very high ones, as the inductor will behave as an open circuit for very high frequenci... |
H: Linear system - causal and memoryless system (integral)
\$T{(x(t))} = \int _{-\infty }^{+\infty }sin\left(t+\tau \right)x\left(\tau \right)d\tau\$
Is this system causal or not? Is it memoryless or not?
At first I thought it was not causal and with memory since the boundaries are from \$-\infty\$ to \$+\infty\$.
I ... |
H: Transmitting input through USB from microcontroller
I am making a device, similar to a cross between a controller and a mouse, and I wondered how I would send input to the computer.
For example:
Transmitting movement, buttons pressed etc.
Also, how would I make it so the computer automatically detects it as a mouse... |
H: How to filter noise/ripple for a JFET audio amplifier?
In my first realization of a common source JFET preamplifier, I encountered a rather predictable problem but for which I was unable to find any documentation: the power supply ripple and noise are reflected in the output signal, which comes out amplified and au... |
H: What temperature should I use to desolder a FPC connector by heating the back side of the PCB with a hot air gun?
I am learning how to use a hot air gun on PCBs.
I saw some videos of FPC connectors being desoldered by heating the back side of the PCB with a hot air gun. I am assuming it is being done to prevent mel... |
H: How to extend up-time after power supply is gone
I just started to work on a small home project. I have an indoor bike that I use quite a lot. The resistance of the bike can be adjusted manually in a purely mechanical way (by tightening a screw). And I have some 24V DC motors laying around, so I thought, why not co... |
H: LED Fails to illuminate, what am I not seeing in my configuration(s)?
I'm working on a super simple circuit, I want to light the LED.
Power Source 1: 5.5v from 9v battery through breadboard power supply module
Power Source 2: 5.5v from lab bench PSU
LED Info: Vf - 3v to 3.2v; If = 20mA;
Resistor: 150 +/- 2% - brown... |
H: Small Speaker with High dB. Loud enough?
I need a compact speaker suitable for a 16mm diameter tubular enclosure. The speaker must be capable of playing voice audio clips with sufficient clarity and volume to be easily hearable and understandable for 1-2m away in a small room. I'm thinking about 30% of a modern iPh... |
H: What resistors for a 4 LED Arduino/breadboard project?
I am currently working on a school project for my work-study. The project is super simple: light up 4 LEDs, in various patterns, using a push button to cycle through the modes. I'm using 4 colored LEDs, a breadboard, resistors, jumpers, and an Arduino UNO.
I am... |
H: How does the second flip-flop in a naive synchronizer "prevent a metastable state from propagating"?
In this very nice answer it's explained that, fundamentally, a two flip-flop synchronizer's basic operation is to prevent the propagation of a metastable state (effectively, an invalid logic level) from propagating ... |
H: Why are drain and source not actually perfectly symmetric?
In textbook treatments, one has that the source and drain of a MOSFET are completely symmetrical and therefore interchangeable -- the distinction is only made by which is at a higher voltage in the circuit in which the MOSFET is used. Gray and Meyer (Analys... |
H: SN74LV4052APW as UART Switch
I am using SN74LV4052APW as UART switch with ESP32-S2 SoC Design. I have 3X UART in the design but since ESP32-S2 supports only two UART channels so I had to use this electronic switch to switch between 2 UARTs. One UART is for Firmware upload via USB and 2nd UART is connected to a disp... |
H: Capacitance displacement probe guard ring circuitry
I am attempting to build my own capacitance probe for high precision displacement measurements. The working principle is simple - a constant current AC signal (~100kHz) is passed through the probe sensing electrode, and the surface being probed is grounded. As the... |
H: Is feedback positive or negative for this closed-loop circuit?
The following is from the book Design of Analog CMOS Integrated Circuit, Page 307.
I think feedback is negative in my opinion.
Here is what I think, see picture below.
AI: Simple analysis: Have a look at the closed loop (the loop gain with Vin=0) and... |
H: Voltage follower generates voltage by itself
I am currently working on a project that requires me to measure a capacitor voltage that can reach up to 250 V.
To measure such a high voltage I first created a voltage divider with very high resistor values so the capacitor doesn't discharge very fast (resistor1 = 10 MΩ... |
H: Confused about skin effect
Why skin effect is respected when it comes to transformers but not to filters, even when they are dealing with same high frequencies?
For example, in full bridge SMPS, with more than 100 kHz, we found that the wire thickness is too small in transformer and too thick in the output filter.
... |
H: How can I drive an LC tank with a transistor?
I've been exploring the idea of making an induction heater.
Mostly I see people using the ZVS circuit to do it, but I would like to get an understanding as to how you would do it if you had an ADC and a microcontroller (where you could switch the transistor/s at any giv... |
H: Mounting an 11W SCR with a Flat Profile
I have two SCRs in my design that will be switching up to 15A at 120-240VAC. The two devices will split the power, with each one conducting a half cycle. I'm considering using the S6025 by Littelfuse.
The power through each device works out to...
(15A * 1.5V) / 2 = 11.25W per... |
H: Active crossover filter for AB AMP
I want to use a STA540 amplifier IC in Stereo plus bridge configuration (page 11, figure 6).
The idea is to have the chip drive two 4 Ohm tweeters and one 8 ohm Mid/Woofer.
Since passive crossover are quite expensive, I thought of using an active one before amplification. Could th... |
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