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H: Connectors for access to four conductors from a 40-wire ribbon cable
I have a Raspberry Pi project I'm working on that will involve connecting three printed circuit boards. I'm trying to figure out a rugged and convenient way to make the connections. The drawing below is a side view of my current rough concept for ... |
H: XO selection for 44.1kHz audio
I'm implementing a WM8804 S/PDIF transmitter in a project I'm working on. The datasheet states that clocks from 10MHz - 27MHz are supported.
What crystal oscillator frequency should I look for in order to support 44.1kHz I2S output given a an input of 44.1kHz S/PDIF?
Edit:
It looks li... |
H: Why do some PCBs have exposed plated perimeters?
I've seen a number of PCBs, largely high speed and RF boards, that have exposed copper, either at the perimeter of the entire board, or in various sections, often with stitching vias.
I've never fully understood the purpose of these. Some explanations I've heard call... |
H: why ARM architecture necessarily dominates the IOT market?
I would like to understand why do we use ARM for routers, cell phones, cameras, refrigerators, smart tv, and everything. instead of using any other architecture like x86.
What are the advantages of using arm for these things?
What would be the problems of s... |
H: Do I have to do anything special if I want to connect to a chip with SWD and SWDIO and nRESET are on the same pin?
I want to wire a MDBT40-256RV3 to a SWD programmer and on the programmer nRESET and SWDIO are on separate pins but on this chip they share the same pin, so how should I wire that?
AI: Just wire SWD and... |
H: What are the advantages and disadvantages of Manhattan-Style routing?
Manhattan-Style routing being the use of expressly east-west planes and north-south planes, using a via and changing planes when a signal changes direction.
Comparing to freestyle routing, which lets define as routing signals in any direction on ... |
H: how to understand SMBus SDA line captured waveform
I am using MCU (L476RG) with PMM240 (power management board) and RRC 2054-2(battery), I am figuring out why SMBus is always busy after sending command to slave, so I captured the waveform when I send command, but I am totally confused, the SMBus address is 0x16(alr... |
H: How do wireless receivers reject noise created by the original signal reflecting off walls?
When a transmitter emits an RF signal it reflects and bounces around all over. If a receiver is line-of-sight with that transmitter then the original signal will hit it first but signals bouncing off walls may hit it soon th... |
H: Securing mod wires to PCB
I have done a few mods to a PCB with 36 gauge mod wire. Obviously this wire is so thin that it only takes a few bends back and forth to break it. What is the best way to secure this in place on the PCB? I have tried super glue but that makes a mess because it flows too easily.
AI: At work ... |
H: Help designing a voltage divider
I said voltage divider on the title, but could be anything.
I have a DC source of 19.7V.
I need an output that varies from 0V to 18V.
I have:
Resistors (1/8W);
1k potentiometer;
5k trimpot;
2N3904;
LM358;
Capacitors.
My only requirement, besides part count, is that both potentiome... |
H: Op-amp input impedance
I was reading the following tutorial from Analog Devices:
https://www.analog.com/media/en/training-seminars/tutorials/MT-040.pdf
They include the following image and state:
In most op amp circuits, the inverting input impedance is reduced to a very low value by negative feedback, and only Zc... |
H: MT3608 gets very hot only handle 1A
In the datasheet they mention the MT3608 can handle up to 2A however in some stress tests with a load tester it gets already very hot at 1A. It is so hot, it is impossible to touch the board, all components around it get very hot because it spread all of the heat via paths. The c... |
H: Sharing the Load: Power Ratings
I have some cheap potentiometers that I would like to use as variable resistors.
The potentiometers have a power rating lower than the amount of power I would like to be able to dissipate across the setup at a fixed voltage, so I have a plan.
Instead of using a single potentiometer... |
H: how to use decoder and motor drivers to power individual motors at 12V?
I have a huge set of motors and they need to powered at specific times and at different voltage levels individually. Basic idea that I had, is to use a demux or a decoder to select the motors and then control them through PWM using any uC(prefe... |
H: Two power sources into appliance (12Vdc)
I am creating powering board for LED strips inside the cacti glass house. It consume 12V DC around 2 amps. I would like to power them up from battery (charged by solar, lead-acid battery 20Ah), but if there is no energy left, switch to DC power supply (12vdc).
I found the an... |
H: What is the transmission bandwidth for a BASK (Binary Amplitude Shift Keying) signal?
What is the transmission bandwidth for a BASK (Binary Amplitude Shift Keying) signal?
Shouldn't it be infinity as short periods of sinusoids are used to depict 1 and 0 to depict 0?
AI: The bandwidth is defined by the pulse shape,... |
H: Help with solving this DC circuit
]2
I tried KVL, KCL and the standard stuff (My knowledge goes up to Super-nodes and Super-mesh) but I have no clue what the 4V source is actually supposed to do? Sorry if the answer is obvious, but I'm stuck on this.
Edit: I've added some labels and added an image of what I came up... |
H: Insertion of transmission lines and effects on reflection coefficient
I have a doubt on a step usually performed in matching network design. Consider a load ZL: a method for getting impedance matching (for instance with an amplifier) is that of inserting a transmission line in order to modify its impedance, like in... |
H: How to test a TRIAC with just a digital multimeter and no external circuit
I need to fix an electric kettle and would like to test the health of the TRIAC BTA20. How would you test this component health with a digital multimeter - without any extra components and ideally without removing it from the circuit?
thanks... |
H: Does an AC wave running through a wire produce EM waves?
I understand that current from a DC source running through a wire produces a magnetic field. However, is the changing magnetic field produced via current from an AC source, technically a part of a EM or radio wave?
If so, do transmission lines produce EM wave... |
H: How many transistors are there in a logic gate?
How many transistors are there in a logic gate?
If anybody asks me, I tell them:
A NOT gate is 1 transistor.
A NAND gate is 1 transistor per input.
A NOR gate is 1 transistor per input.
An AND gate is basically a NAND gate + a NOT gate, so it takes 1 transistor more ... |
H: Odd PCB Layout for Voltage Regulator
I am reverse-engineering a board which has a Xilinx Spartan 3E FPGA, with VCCAUX powered by a 2.5 volt regulator. Below is the PCB layout for the regulator part of the circuit, and something seems very fishy to me.
My apologies for the horrible pixelation, this was the highest... |
H: Negative Voltage creating Sinking Terminal
For powering a RS485 circuit, I am requiring a Negative Power Source.
I was thinking to split a standard power source with 0V, +6V and +12V, using the +6V as ground with LM7805, and using some LM7805|LM7905 (or similar) devices for regulate into +5V|-5V.
In this case, the ... |
H: STM32F4 Discovery board only works in DEBUG mode
I generated my project with STMCUBEMX with CAN, SPI, I2C peripherals and did some coding on top of it. Code basicly polls the CANBUS, stores data to some IC over i2c and sends the processed data to the connected nodemcu over the SPI.
It was working as it should until... |
H: What is the intended use of the 400 Hz-rated power supply on osciloscopes?
The power supply of many oscilloscopes and other test equipment from different manufactures are commonly rated for 400 Hz operation. For example, Tektronics MDO3000 is rated to work at 400 Hz at 115 VAC. Rigol MSO7000 is rated at 100-240 VAC... |
H: What is the purpose of the T-568 ethernet color code standard
A question came into mind. as i was crimping some ethernet cables at home.
I am talking about straight cable not crossover cables.
What is the true reason for the T-568A or T-568B color standard. Because just arranging the wire in sequence will work jus... |
H: Does position of resistor matter in this schematic?
This is the schematic:
Above picture is the crystal resonator part of Arduino ATMEGA328P micro-controller, in the green rectangle they placed the resistor in parallel before the crystal and in Arduino UNO also it's before the crystal.
What does this resistor do?... |
H: How to find the right smoothing capacitor for rectification circuit
I am creating a power supply which will need to convert the 24vac to 5vdc. I am thinking of using a rectifier to convert ac to dc, then a capacitor to smooth out the voltage, then an LM2596-5 to drop it down to 5v. I am having trouble with selectin... |
H: Is back emf inductance in a ignition coil circuit symmetric for on/off cases?
I was trying to understand how an ignition coil circuit works practically, and came upon this website explaining the behavior of an ignition coil when subjected to changes in voltage:
http://www.learnabout-electronics.org/ac_theory/induc... |
H: Inverting negative voltage back to positive with LM324
To be able to measure the value with an Arduino Nano I want to convert the negative rail voltage to positive. I tried to build a simple inverting amplifier with unity gain using LM324. The supply is +/- 10V.
The voltage is converted but scaled down. When I meas... |
H: JFET stabilised wien bridge component ratios
I find myself in need of a sine wave oscillator and have decided on the wien bridge. I have followed all the tutorials but have a few questions that do not seem to be answered elsewhere.
Firstly, I understand the ratio between Rf and R3 determines the negative feedback ... |
H: Basic Capacitor
In a circuit there are two capacitors, Capacitor a and Capacitor b, now both of them have the same voltage values but different farad values, now, I know this must be a basic question, but I'll like to know:
What is the difference does the capacitors make in the circuit, they both have the same volt... |
H: 5V 4-pin Noctua A4X10 on Raspberry Pi
I want to connect a NOCTUA NF-A4X10 5V PWM 4-pin fan to a Raspberry Pi 3B.
The below is the circuit I'm planning to use.
(EDIT: Flyback diode (such as a 1N4001) is not needed since Noctua already provides polarity protection, and a brushless fan typically already has it);
(EDI... |
H: Verilog - Wiring multiple hardware instances together
I am very new to Verilog and digital hardware implementation.
I want to instantiate multiple instances of a hardware block, place them side-by-side, then wire them together (ie. one block's output is the next block's input). What makes it complicated is that I ... |
H: Maximum Gain and Maximum Power Transfer
I am a bit confused about Impedance Matching for maximum gain and for maximum power transfer.
I knew that the conjugate matching between, for instance, an amplifier's output port and a load Zl, is given by the condition Zout = Zl*. Under this assumption, reflection at the int... |
H: Short circuit detector (autoreverser circuit) using current sensor and switching relay
First of all I’m not electrical engineer. The original idea is described here.
It is a model railroad problem. The rails are carrying a power signal (DCC) 12-18 V. The frequency is ~17 kHz. It is a square wave signal described he... |
H: Audio Equalizer LTSpice Simulation
First, I'd like to say i'm not experienced on circuits, but i'm doing my best to learn.
I'm trying to create an audio equalizer which is capable of amplifying low frequencies (20Hz-200Hz), mid frequencies (200Hz-2kHz) and high frequencies (2kHz - 20kHz).
At the same time it shoul... |
H: Printing current when using sinus voltage source?
I am very new to ngscpie, and I need a simple example of very simple circuit composed of two components, a resistor connected to voltage source of sinus wave via two wires.
then to print or plot current applied on the resistor and see the sinus wave, where resistor ... |
H: Does 1200mAh Lipo battery will kill my circuit? help me to read the data sheet please!
I've found old arduinio project from Gitlab which runs the circuit with Lithium Ion Polymer Battery - 400mAh Unfortunately i wont be able find any Lip 400mAh in my country.Lucky enough i found one supplier has 1200mAh Lipo but i... |
H: To connect Active GPS Antenna wires on PCBA should Solder or use Connector
Will it make a difference if I solder or use the supplied SMA type connector to connect the wires of Active GPS antenna on PCBA?
I am using gps antenna of this type.
AI: I would definitely recommend a connector.
If your antenna should break... |
H: Ultrasonic module Water proof vs non-water proof types
Ranging SR04 Ultrasonic modules are available as water proof and non-water types.
In the water proof types SR04 modules there is only 1 sensor while in the non-water proof types SR04 there are 2 sensors, 1 as transmitter 1 as receiver. How does the single se... |
H: Is is safe to let my PWM charge my 12V battery at 14.8V?
I have a 12V battery linked to my solar panels.
In the middle I have a PWM charge controller, that is configured by default to charge the battery if Voltage if lower than 14.8.
At night, battery goes down to ~13.8V. (Which I think is the voltage of the full b... |
H: step up from 2 AA to 3.3V
I've read some related questions, but I was not able to find/understand a proper solution
I'm using 2 AA batteries to power a SAMD21 MCU (arduino mkr series), a DS18B20 probe and a MCP3424 ADC. My problem is that temperature probe and ADC need more than 3V or 2.7V (respectively) to work pr... |
H: Controlling the current through multiple LEDs linearily and efficiently
I have around 100 infrared LEDs, each with an adjacent phototransistor to detect small differences in the distance of several objects (QRE1113).
As the objects materials differ, I want to be able to calibrate the intensity of every emitter sepa... |
H: If my circuit is electrically isolated, do i have to worry about a polarizing effect on my sensor's output?
If I am making a conductivity sensor one of the things it need to watch out for is polarizing the water.
easiest way to do this is have the output output signal of the sensor have a +/-0.2V square wave.
i wa... |
H: Thermal Glue solvent
I have a PCB with many chips on it - it's a "hashboard" for an ASIC bitcoin miner. There are 63 chips on every hashboard, and each chip has a small heatsink on it.
I tried heating the heatsinks with a hot air gun to remove them, but most of time the chip comes off along with the heatsink, and t... |
H: Opamp input offset voltage...common mode?
Looking at the datasheet for an OPA197 opamp, I see this:
What is the circled expression trying to tell me?
The common mode voltage is equal to the voltage at the non-inverting input minus 1.5 V which is equal to plus or minus 10 µV? I can't follow that.
Where does the 1.... |
H: IRF520 max frequency
I'm having trouble supplying 300mA to an led COB using an IRF520 MOSFET as PMW, controlled with arduino nano.
What is the maximum Frequency, in which I can turn the led on and off in this setting?
In the IRF520 DATA sheet:
Turn on delay time: 8.8ns
Rise time: 30ns
Turn off delay time: 19ns
Fall... |
H: Are phase angles in filter transfer functions primarily for stability?
I see transfer functions and bode plots (magnitude and phase) and it occurred to me, that I don't really use the phase plots at all. My career experience seems to have gotten away without having to use or calculate them except once where I had a... |
H: What is internal generated voltage of synchronous motor?
A 208-V Y-connected synchronous motor is drawing 40 A at unity power factor from a 208-V power system. The field current flowing under these conditions is 2.7 A. Its synchronous reactance is 0.8 Ω. Assume a linear open-circuit characteristic.
The answer is g... |
H: Guidance on the use of pins of LM1117
I plan on using this 3.3v regulator
It has 4 pins on the SOT-223 package
I plan on doing the following ( but want to check )
Pin 1 - Gnd
Pin 2 - Vout - 3.3v -- Tied to pin 4 feeding my circuit
Pin 3 - Vin - 5v Supply
Pin 4 - Vout - 3.3v -- Tied to pin 2 feeding my circuit
Do... |
H: Audio amplifier mono operation and power consumption
I'm looking to use a PAM8406 in Class-D mode, with only the left channel active.
The datasheet doesn't discuss how to handle unused pins for the right channel to "deactivate" that half of the amp.
Should I connect INR, OUTR+ and OUTR- to ground?
If not, what can... |
H: Can a castellated PCB/module have electrolytic capacitors in it?
We're designing a small module (3in x 3in) that will have castellations on the edges for connection. I just watched a video on castellation PCB design. The video talked about the module going thru reflow several times. Once to build the module and the... |
H: Identification of two components
Can you help me identify these two components? I cannot find information on them on the web. They appear to be ceramic filters of some kind.
Front of Component 1:
Back of Component 1:
Front of Component 2:
Back of Component 2:
AI: They are resettable fuses, the big one is 600V fo... |
H: Using Pointers to implement a filter
I'm trying implement a fairy basic filter, and right now I have just some simple test code for me to enter in values. It errors out on the line when it gets to where I call the function I have written. I am fairly certain my error is coming from how I am using the pointers but I... |
H: Resistor & capacitor are getting too hot
I made a transformarless power supply with capacitor. When i connect it on ac, it light the leds. But after some second the 100ohm resistor and 470uf capacitor get too hot. Its too hot that i could not touch it then. What's the
problem . Pls help me.
AI: With 12Vdc drawn f... |
H: What Resistor to use between Source and an IC
I'm trying to make a clock, and as part of that I need to power some IC's. To give a specific example I'm looking at the TI SN74HC163 4 bit counter. After some searching around, I found myself directed to this (basically Ohm's law) equation from the sacred texts:
The ... |
H: Surface Mount Resistor Clip?
I have a goofy idea: a user is given a PCB and a pack of surface mount metal film resistors. To configure the board's settings, the user places various combinations of resistors into several 'sockets' or little clips on the board which surface mount resistors fit in in the same fashion ... |
H: Refraction vs Reflection in Ultrasonic sensor for water level detection
I want to use ultrasonic module JSN-SR04 for detection of water level inside tank. The US module has single sensor for Transmission and Reception of US signals as shown below.
I wonder if US sensor will work reliably for water level detection... |
H: Can not recognise this piece of equipment. It is attached to the mains
It is normally quite noisy, but has gone silent.
AI: The black box with white text in a circle is a week timer.
Not how there are Roman numerals: I - II - III - IV - V - VI - VII
which is 1 - 2 - 3 - 4 - 5 - 6 - 7 for the days of the week.
Ther... |
H: Load cell accuracy: rated output vs. full scale
I'm currently shopping for some subminature load cells for a research project. I've narrowed it down to two options, the FUTEK LCM100 and the Burster Model 8417. Problem is the two specify their accuracy in a different manner.
Futek gives the standard Nonlinearity, R... |
H: How to calculate voltage-power to lower voltage-power?
I have a solar panel 18V 2W. How do I calculate how much power that is at 5V?
Thank you in advance
AI: You will have 2W less losses at 5V, which means more current.
2W / 5V = 0.4A max assuming no losses... |
H: What does this value mean in a BJT datasheet?
In the switching characteristics section of a BJT datasheet I often see test conditions like \$I_{B1}=I_{B2}=1mA\$. I understand this is the base current, but what exactly do they mean by \$I_{B1}\$ and \$I_{B2}\$?
Example: https://www.mccsemi.com/pdf/Products/MMBT3904(... |
H: Why do we need a bootloader separate from our application program in microcontrollers?
Why do we need a separate program in the same flash program memory of a microcontroller, specifically STM32F103, which is called a bootloader?
What is special about it to keep it separate from the main application program?
Gener... |
H: Can we extract CTR parameter of an optocoupler from its SPICE model this way?
Regarding 4N26 optocoupler, I tried to obtain the following results from the datasheet by LTspice:
So as in the test condition I set the forward current 10mA and I set the Rload such that Vce = 10V.
If my setup is correct, the LTspice s... |
H: DC Power Connector Type
I have looked at many DC connector types but still couldn't find what type is the following connector. It's not XLR or Power DIN. Any ideas?
It's similar to GX16-4 4-Pin 16mm Aviation Pug but it's not the same
AI: I am quite certain it's from the Hirose HR-30 series.
You should measure the ... |
H: What units are kpts?
I am parsing data from a Siglent SDS2000X oscilloscope. The first chunk (0x00 - 0x003) is for wave_length. The data sheet states that for arbitrary waveform generation, the wave length is "16 Kpts".
What unit is Kpts? Kilo-Points? How would I convert that to a wavelength unit such as meter... |
H: ( How-To ) Ultra Low-Profile PCB Stacking
Recently I found myself needing to stack two small circuit boards on top of each other for a modulation project. The problem is that the areas I want to connect together on the two boards have no components or traces on them, and traditional pin-style stack ups (even machin... |
H: What are the options of PCIe dev boards these days?
do you know if there is any fpga PCIe dev board that would support adding/removing pcie capabilities and examining tlps?
AI: This is not a feature of the dev board so much as a feature of the PCIe hardware on the FPGA. At any rate, the PCIe hard cores on Xilinx Ul... |
H: DC Boost Converter stepping up voltage very slowly, if any
I've come across DC boost converter and told myself - why not to try it as well? So I started building a simple circuit which includes BD243C NPN Transistor, ATTiny13A programmed to give some pulse to the Base of the transistor, 16 uH inductor, 82 uF 450 wv... |
H: How does full wheatstone bridge with strain gauges work?
I have gone through a number of tutorials on Wheatstone bridge and how to use it to sense load using strain gauges. I have also gone through the calculations where one of the resistors of the Wheatstone bridge is a strain gauge and how the voltage we measure ... |
H: Using a step by step relay along with a solid state relay
I have a step by step relay which is connected to a light bulb and to a manual switch.
In parallel with the manual switch I put a SSR. I command the SSR to be on for 0.5 seconds, however the light would not switch(although the manual switch works).
Is there ... |
H: RJ-45 with only four wires?
Dig through a junk drawer, I find a long cable with RJ-45 on each end. Definitely not RJ-11. It has only four wires. What might it have been used for?
I'm not expert on wired ethernet, but in forty years of tech work, I've seen only six and eight wire connectors, mostly eight. This i... |
H: Optocouplers common resistor
I have seen optocoupler series with common cathode and resistor on every anode. My question is whether or not one resistor on the cathode side will be sufficient, with the right wattage, of course, and what is the reason behind these many resistors.
simulate this circuit – Schematic cr... |
H: What is the current draw during load on the LM1117 3.3v
I am looking at using the LM1117 3.3v voltage regulator.
I would like to determine the current draw to power the regulator's function, during output of something near 650mA.
All I can find is entries such as :
Quiescent current: 10mA
Is that my draw figure? I... |
H: Gain with inversing Op Amp on Equalizer
I know I posted a question about this circuit before, but I'm running into a problem. I know this is a terrible equalizer design but I'm trying to learn to put in use what I learnt with Op Amps and transfer functions.
I did the following equalizer using 3 band-pass filters wi... |
H: Filtering an ADC input with an RC low-pass filter
I use an instrumentation amplifier to amplify low voltage signals from a sensor.
The max. amplified output voltage is 3V. Im using this ADC: http://ww1.microchip.com/downloads/en/DeviceDoc/22088c.pdf.
It has 4 channels that are multiplexed. Every 5 seconds all 4 cha... |
H: Problem driving IPB065N15N3G MOSFET with HCPL-316J driver
I want to drive an IPB065N15N3G MOSFET. I am making a boost converter. The driver I am using is the HCPL-316J (a combined optocoupler and driver). Below is a picture of my schematic.
Please tell me what is the problem in this schematic and why can I not get ... |
H: Microprocessor architecture bits vs bus sizes
I am ready following on this website:
"Another big difference between 32-bit processors and 64-bit processors is the maximum amount of memory (RAM) that is supported. 32-bit computers support a maximum of 4 GB (2^32 bytes) of memory, whereas 64-bit CPUs can address a t... |
H: How does the DW01A prevent overcharging and discharging?
I am not that familiar with electronics, it's just a hobby.
I am reviewing the TP4056 and DW01A ICs that are used for battery charging.
Actually there is nothing special about these ICs but I was wondering how the red marked area works.
I know the two DW01A p... |
H: I just purchased a batch of TL081CP opamps and would like to know what the codes on the bottom mean
There is a random marking on each one. none the same. What does this mean? e.g. 03, 1h31
In my batch, none are the same with leads me to think they would not be bach codes.
AI: According the datasheet, page 21 the de... |
H: Voltage loss on DC circuits
I want to connect 4 bulbs in parallel. The bulbs need 12V DC and rated 18 watts. P=V*I, that means I=1.5 A on each bulb. From that the resistance of the bulbs are 8 Ohm (R=12/1.5). The circuit will look like this:
simulate this circuit – Schematic created using CircuitLab
But in real li... |
H: H bridge inverter
I am trying out an H-Bridge inverter using GaN FETs at 140 kHz. The schematic is as follows. (In the experimental prototype, I used TI's LMG5200 and the load is connected via a full-bridge rectifier.
The switching waveforms are
The circuit works fine when it is not loaded. The output of the inve... |
H: Whats the purpose of 0R in Sonoff POW
I'm designing my own Sonoff with ESP32, with power monitoring capability. Now before I start my own design, I took a look at Sonoff design. In the Sonoff POW the power metering IC has a 0R resistor, while the datasheet of HLW8012 did not have any 0R resistor. The 0R an an SMD 1... |
H: Clock Dividers with Clock Domain Crossing
I am doing a design in FPGA that looks like this:
100 MHz is the clock available in my FPGA board. It feeds Module 2. Module 1 is needs a slow clock of 10 MHz clock. So I used a clock divider with flip flops. I thought of not using PLL to make my code purely RTL. Module 1... |
H: Why is the audio input from the microphone connected to the inverting input on the TPA6111A2?
As far as I know, when we connect a signal to the inverting terminal of an op amp, we get an amplified output which is 180 deg out of phase from the input. Going through the datasheet of TPA611A2, the input from the microp... |
H: measuring -3V with 3 resistors voltage divider
I know (or may be think) that I can scale the measurement of a 0 to -3.1V external battery to a analog pin ADC range of 0 to 3.3V, but I'm unable to calculate the resistors.
I've been trying how to do this by thevenin, but with no luck...
The schema (I think) would be ... |
H: Pi Filter Option
I put a (C-L-C) Pi Filter in series with my antenna trace on a new design, like so:
source
The reason you put one of these circuits in, as I understand it, is just in case, during compliance testing (i.e. FCC / CE) you have an issue with your antenna matching causing a failure, you have a decent ... |
H: How do we interpret frequency from fft command in matlab?
How do we interpret frequency from fft command in matlab? When I apply fft to a sampled function(@ Fs) and I get peaks at some values in the fft array. How do I know what frequency in Hertz does it correspond to?
AI: The output of the fft function will go fr... |
H: How to attenuate a cheap MP3-player speaker?
I have a cheap single-chip MP3-playing speaker. The kind you you get off eBay for $10. I want to make the output quieter (so I don't always have to adjust the digital volume controls).
The amp is a LTK8002D Class AB Audio Amplifier
I want to do this in a way that doesn't... |
H: Help making a adder/subtractor on Logisim
I have attempted to make an 4 bit Adder and Subtractor circuit on Logisim, but i've came across a problem. So the Adder works but the subtractor doesn't. When i do subtraction the 1 thats carried in is carried throughout the circuit. When i do 1000 - 1000 it gives me 10000.... |
H: Weatherproofed Connector For Outdoor Valve
To connect an electronic outdoor DC solenoid valve to a timer, I am getting recommendations to use a silicone-filled wire nut OR solder and heat-shrink. I understand that wire-nuts are simpler for those without a soldering iron, but will heat-shrink technically form a mor... |
H: Electric arc from a supercapacitor bank?
I have really no idea and this is not a homework!
Given you would work with existing components.
Imagine you would like to build a small electric arc furnace say 1-50g capacity; is it realistic to run it for some seconds with the charge from a supercapacitor bank to complete... |
H: Measure 10kV with 600V rated multimeter
My multimeter is rated for 600V but I need to measure a 10kV AC source. I was thinking of building a voltage divider but I wouldn't know how many resistors it would take to safely measure this high of voltage.
AI: 10 kV AC is measured using a voltage transformer.
Figure 1. S... |
H: Does Hall flow sensor require an optocoupler when using STM32 MCU?
I'm using an STM32F103 to measure water flow through a pipe using Hall flow sensors. My power supply is 12V DC to 5V/3.3V DC. STM works with 3.3V and Hall sensors with 5V levels. I've configured the TIM4 as Input Capture and connected it directly to... |
H: How is Q for surface acoustic wave devices measured?
I do not have a good understanding of Q, the quality factor.
I get the basic concept that it has to do with energy losses within a system, particularly oscillating systems like resonators. Higher Q has less damping and will ring a longer time, while lower Q are t... |
H: MOSFET capacitance clarification
Two part question here:
Are there ways to directly test the input and output capacitance of a MOSFET, Ciss and Coss?
Due to internal inductance and capacitance, is it possible for a standalone MOSFET to resonate at certain frequencies?
AI: YES,YES
1) See best datasheets for test me... |
H: IR Sensor Replacement
I am currently designing a circuit, where output is switched on and off as obstacle passes IR (Infrared) beam, produced by IR LED and received by IR sensor (IR photo-transistor). The problem is that IR sensor is greatly affected by light from surrounding sources, like celling lamp. IR sensor's... |
H: How to connect male wire to stiff piece of metal with holes
This is my second day playing around with Arduinos, so I don't particularly know hardware-related concepts and terminology. I'm trying to connect a simple male wire to a button (see image). The only thing I've tried is simply threading the hole with the pi... |
H: Can two lights be switched between without an "ON-ON" switch?
The schematic above shows our problem. We need to be able to turn on light A when a switch connected to light A is closed and then turn on light B when the switch is open.
There are a few constraints:
the lights must have a common ground
they must hav... |
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