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H: Why do we still use cable for a lot of forms of data transmission?
Like many people I'm often annoyed by ugly cable clutter, especially when it's long distance. In my opinion it would be ideal if cables could be eliminated altogether, so that you'd just have two corresponding plugs without the cable, which you plug... |
H: opto isolated arduino input
I want to protect a pin with an opto isolator to get an external signal from an electrical meter (35VDC max, 50mA max, 240ms pulse width). The purpose is to count the pulses.
Do you have some schematics examples for that ?
Thanks
AI: This shouldn't be too hard:
Vcc is the +5 V Arduino... |
H: how to charge a steel ball
I have a 2 mm radius steel ball and I want to charge it in a 0.025 Coulomb charge. Can I do that domestically or the charge is too high? And how can I do that assuming I don't have another conductive material that I know it's charge?
AI: Not if you value your life!. The capacitance of a s... |
H: Low threshold N-channel MOSFET
I have a circuit which does something not important, but it results in an output being normally low, and then on activation climbs to a little below Vcc. At the moment, it appears my Vcc is 1.8 V and the signal gets up to between 1.2 V and 1.4 V. I want to use this signal to control t... |
H: Using a pc power supply, any risk to electronics?
Possible Duplicate:
Choosing power supply, how to get the voltage and current ratings?
I have a pc power supply which I modded to use as one for my projects. It's really cool, and I love it.
I just have a question though. Say I am using the 5V port with a device ... |
H: Does the capacitor dielectric experience heating due to rapid charge/discharge cycles?
Does the dielectric in a capacitor when subjected rapid charge/discharge cycles heat up?
AI: Yes, but only to the extent it is not a perfect capacitor. A perfect capacitor is not capable of dissipating energy, which means it can... |
H: What's the difference between field-effect transistors (FETs) marketed as switches vs. amplifiers?
For instance, the J108 JFET is listed as "N-Channel Switch", and the datasheet mentions the RDS on resistance, while the J201 JFET is listed as "N-Channel General Purpose Amplifier" (and the on-resistance would have t... |
H: What should I look for when shopping for an ESD bench mat?
I would like to get an anti-static mat for my bench top and found these two:
DigiKey: Table mat ESD blue 2X4' rubber
Mouser: Antistatic Control Products 2X4' blue table mat
What should I look for when shopping for an ESD bench mat?
AI: ESD precautions:
I... |
H: Two same ADCs produce different result for same signal
I have two ADCs (the model AD9248BST/BCP-65, with the default configurations, not "cross-calibrated"), that are feed the same constant point-to-point voltage. The returned values, however, differ by an order of 7 bits.
The datasheet (see page 3) specifies that ... |
H: Arduino/Atmega with TIP120/121/122 transistors: base current question
I am learning about transistors, and can't seem to find the answer to a few questions which are stumping me. I will be referring to the TIP120/121/122 Darlington Transistor.
As I understand transistors so far, I need to apply a current from
my A... |
H: What's the difference between small signal bipolar junction transistors (BJTs) marketed as switches vs. amplifiers?
For instance, the MMBT3904 and MMBT3906 BJTs are listed as NPN/PNP Switching Transistors, and the datasheets mention the switching times, while the BC846 and BC856 BJTs are listed as NPN/PNP general p... |
H: What are the differences between a gyroscope, accelerometer and magnetometer?
What is the difference between a 3-axis gyroscope, 3-axis accelerometer and 3-axis magnetometer? How do these sensors work? Why are all 3 used in some devices like smartphones, tablets, quadcopters etc.?
AI: They are three sensors that ar... |
H: How to make a device that keeps water in sink and bath at desired temperature?
I have tight taps in my sinks and bathroom which are difficult to control — it's either too hot or too cold and never easy to manually set the preferrable temperature. I'd like to solve this old problem electronically.
I figure I'd need ... |
H: AC-DC converter, transformer modification how-to
I would like to wire an AC-DC converter based on a datasheet schematic. I try to describe my problem. I would like to increase the max current output. The AC->DC converter has a bjt driving a transformer at about 10 khz. I can manage how to change that driver to supp... |
H: Sync video with data
When I have a datalogger and I want to sync a video-file to the recording, what would be an easy method? The logger and the camera both have an internal clock, but they may not be set exactly to the same time, so I cannot use those timestamps to sync the start, and during long recordings they m... |
H: Difficulties of I2C over wire
I want to link a PIC16F1825 and a TCN75 temperature sensor via I2C. The temperature sensor is about 1m from the MCU. Can somebody enlighten me on whether and what kind of difficulties I am going to face by running I2C over wire? I read that I2C can be quite noise sensitive especially a... |
H: Modelling MEMS accelerometer's measurement noise using datasheet (ADXL330)
I'd like to model an Analog Devices ADXL330 MEMS accelerometer using data provided in its datasheet to estimate measurement noise. I'm using a simple mathematical model defined in the paper "Non-linear complementary filters on the special or... |
H: UNO board turned hot
Maybe this is a stupid question to ask, but I am still wondering. I have this kit, I mounted the LCD on the UNO and connected their headers. After downloading the sketch, I used a power line to see the display content as I needed to picture it. But after a few photo shot, the UNO became hot. Is... |
H: Color problems when turning a CRT TV set into an oscilloscope
I found an old CRT TV set in the garbage. It didn't work, always showing the "snow effect", even when I connected it to another device via the SCART port.
So I followed an online tutorial to make it into an oscilloscope. However, I encountered some probl... |
H: How can a capacitor in a disposable camera shock you?
The battery in a disposable camera is usually a single 1.5V AA battery. It charges a large capacitor. When the capacitor is fully charged, it will contain a voltage very close to 1.5V correct?
If one was to touch the charged capacitor, it will shock them. W... |
H: Talking to the Cortex M3 (Stellaris EKS-LM3S1968) under linux
I've searched around quite a lot, but haven't found an easy(ish) way to load programs onto the Cortex M3 using Linux.
I have tried using the summon-arm-toolchain https://github.com/esden/summon-arm-toolchain/ but it was having problems downloading one of... |
H: How can I convert the current from a fan to the microphone headset input on an iphone?
I am working on creating an anemometer (or wind meter) for the iPhone. I am a programmer and know exactly how I could do this on the software side of things, but I am a complete noob when it comes to electronics. I have seen ma... |
H: Programmable USB RF transceiver
I've been trying, and failing, to find a USB RF tranceiver that I can program or that has an API I can use. Does anyone know if such a thing exists, or suggest how I could about creating one?
AI: Connect a suitable RF transceiver (I'm using the cheap nRF24L01+ modules that are availa... |
H: Why is a datapath in microcontrollers always a power of 2 wide?
Microcontrollers data paths are always a power of 2 wide: 4 bit, 8, 16, 32 bit, etc. Even PICs which use 12-bit wide instructions are 8-bit controllers. Why? Is there any design advantage to this? What's wrong with a 12-bit databus, or a 7-bit controll... |
H: How do I test a bridge rectifier?
I got a mess of components at an auction a couple weeks ago, including an unmarked box of unmarked bridge rectifiers. They're about 1" square & 1/4" high if that makes a difference in terms of an input voltage for testing. I don't know if there are ANY inferences that can be made f... |
H: Can an audio circuit be powered by a switched-mode power supply?
Most audio circuits are powered with large, heavy transformers and a small ripple after smoothing. SMPS are smaller and more efficient. EMI can be shielded by a metal enclosure and the output filtered for noise suppression.
Especially where the power ... |
H: Routing considerations of analog signals on twisted pairs
I'm designing a part of a system that will receive 4 analog signals carried on 4 twisted pair cables which are input to an ADC. These signals are low speed (probably in KHz) bipolar ranging from -10V to +10V that should be sampled every 30us. The maximum all... |
H: How to measure a short of power amplifier in car?
Recently my old amplifier in car has got a defective contact on one of the switches, so I decided to unsolder the old one and solder a new one. Unfortunately the amplifier caused a short as I connected it to the battery again (I don't know how this could happen, may... |
H: Charge a single AA battery in a double charger?
Most cheap AA battery chargers charge two batteries at a time. Many devices use 1 or 3 AA batteries, meaning it's difficult to make sure you've always got two compatible batteries in the charger.
My fairly limited understanding of chargers is that they trickle feed e... |
H: Why would an input pin have both a pull-up and pull-down resistor?
In his answer detailing the various types of input pins, Russell McMahon leaves the following note [referring to input pins]:
there are special cases where a resistor to high and low at once is useful
What are the special cases where both a pull-u... |
H: Power supply noise in audio
I have what is surely a classic problem with regard to power supply switching noise and audio but I am unable to sort myth from reality with regard to what I found so far on the topic.
Setup:
I have a notebook with an external power suppy and/or battery
A radio receiver which has its ow... |
H: What electronic component of a computer produces (sound) noise?
Certain mechanical components of a computer produce noise, such as speakers, fans, harddrives and disk readers.
Can electronic components of a computer (transistors, resistors, capacitors, ICs, screens, power supplies, etc.) also produce noise, or is n... |
H: How does autoranging work in a multimeter? What is the circuit?
I was curious how this is done. It seems you would have to vary the voltage and current to measure resistance from 1ohm to 10Mohm.
AI: The multimeter does exactly the same as what you would do manually with a non-autoranging meter. Suppose you have a 3... |
H: How can I find out which wires are the primary wires on this transformer?
About the amp:
This is from an old solid state audio amplifier with an AM/FM tuner. No digital parts or ICs were inside. It was all point to point. Unfortunately I threw out the amp and didn't write down the number and now I am trying to use ... |
H: How does the HD44780 LCD work at the low level?
I'm not asking for a driver specifically, but how exactly it works.
I looked up the 2 chips that were in it. HD44780A00 and HD66100F to be exact. I'm assuming one is a display driver? And the other is a segment driver?
I guess I'm looking to learn how, in this most ba... |
H: BJT, resistor, and diode work but ULN2803 does not
I am trying to control some 5V relays with a mC. At first I went with using a BJT, a 470 ohm resistor, and a 1N4004 diode to control each one of the relays. Each mC output pin is 5V, 40ma. This setup worked well.
I wanted to see if I could do better so I am tryi... |
H: Adding decay (fall-off) to comparator circuit
Following this circuit:
I'm trying to create a slow decay of the peak, like so:
Op-amp output is controlling a dimmer pin of a LED driver.
I want the LED to fade out smoothly after a bang.
AI: Add a peak-detector circuit. If the next stage has a high impedance a simpl... |
H: Why is there a delay in a common anode 7-segment display?
I have a common anode 4-digit 7-segment display. I have each segment cathode connected to a 330-ohm resistor, and the resistor is connected to a shift register. Each segment cathode is connected to the same shift register. Each common anode is connected t... |
H: Proper assignations of current directions
What is the best way to know the proper direction of current? Lets say we have this circuit below:
The correct directions are given below:
What are your techniques to know which is the proper way? I'm afraid that if I choose the wrong direction, then the results will be... |
H: Diode clamper analysis
Why is that when we analyze diode clamper circuit, we always start thinking with the first negative cycle (they say the point where the capacitor charges up)? Whats wrong with starting with the positive half cycle first? Thanks.
AI: Which cycle charges the capacitor depends on the polarity of... |
H: applying nodal inspection technique to supernodes with dependent sources
I was about to apply nodal analysis via inspection (to make it faster) to the above circuit, yet as we can see, it has a dependent source. So listing the equations for node(1 and 2) supernode a:
$$v_1(\frac{1}{2} + \frac{1}{6}) + v_2(\frac{1}... |
H: Audio Capacitor Values
I'm looking to stock my capacitor drawers and I was just looking through trying to find standard values or some kind of list for them and I couldn't find a really good list of standard values for audio applications and other analog circuits.
I'm looking for polypropylene capacitors (these see... |
H: Signal integrity at 40 MHz with parallel signals
I have to design a board with an 8 bit parallel port that carries 40 MHz signals. It is not possible to wire them very short and in parallel (I am sure the wires will be about 7 cm long), so I have to wire them separately in pairs of 2 or 3 wires together because my ... |
H: Are those some kind of timed-resetting fuses in DMMs?
Yesterday, I did something dumb, in a hurry. I wanted to check the AC voltage at the terminals of a hair-dryer, to determine the voltage being applied to the terminals of the AC fan behind it. However, in a hurry, I plugged in the positive lead, to the unprotect... |
H: How can I design a circuit that will turn on when a wire is cut?
I'm trying to build my own cable lock alarm (for science!) and am having trouble figuring out a way to detect that a wire has been cut.
The circuit has to
Use no power at idle (or at least, very very little so that the batteries don't have to be chan... |
H: Arduino and Display in different rooms, possible?
I only wondering which four pins I have to connect for the LCD4884 from SainSmart, because I want to have Arduino and the LCD in different rooms. Is it possible?
AI: Well your question doesn't really have anything to do with the arduino and the display being in diff... |
H: arduino best serial communication solution
During the last two days I was googling and searching about serial communication tools for Arduino.
I found a lot of tools like :
Node.js through node-serialport
Python through pyserial
Javascript through breakoutkjs using Frimata
So from your experience which is the... |
H: Resistors - metal film or carbon film and what values?
I am buying a bunch of resistors as a start to my electronics hobby. These are the values I have chosen:
100, 470, 1k, 4k7, 10k, 33k, 47k, 100k, 470k, 1M
Most of my projects will involve microcontrollers, such as the Arduino and other AVR ones. I have two quest... |
H: Which LED driver?
My company wants to produce LED lamps. In order to do that I searched a lot for LED drivers. They are lots of LED driver circuits in the world and IEEE papers or patents.
I want to chose between them but I can't find the best commercial LED driver for different uses such as indoor, outdoor etc.
Ca... |
H: Join together two flexible electrical cables
I have 2 electrical cables (audio cables) of same diameter that I want to join, with a connection as discreet as possible. It is common to use some dominos for this kind of task, but these are really to visible. In a perfect world, I'd like the connection to be nearly in... |
H: Why are vias placed this way on a PCB?
I used to check complex commercial PCBs specially those of graphics cards to see how professional PCB designers do their layout and learn from their techniques.
When I checked the card shown below I noticed two things regarding the placement of vias:
(A higher resolution image... |
H: Battery management circuit for Nokia BL-4C / 5C Li-ION batteries
Nokia BL-4C / BL-5C are 3.7V, 700-1000mAh (variants) Lithium-ion batteries, which are available in abundance and at very low cost ($4 - $7 a piece), since these are used in entry level Nokia phones, sold in most developing countries.
These batteries ... |
H: How to choose correct resistor with proper wattage and ohms for 6 leds connected in a serial circuit?
Let's suppose I've six LED lights with each 3.2 Volt and 20mA and all six of them are connected in one serial circuit. I know there is better setup but for this I'm using this circuit setup.
I'm using a single pow... |
H: How to set up a PLC for hobby home automation project?
I want to use PLC to do security, temperature and light controls. I took case in PLC, but I don't have real world experience to set up a PLC system. Since I do not want to spend too much (less than USD$400 for PLC and HMI), would anyone please suggest me what ... |
H: Input stage for ADC with operational amplifier
I am trying to make a voltmeter with a 10-bit ADC. The ADC can measure only positive voltages so I have made an input stage with Operational Amplifiers.
The idea of the circuit is to transform any negative voltage to positive. V1 is the voltage output and V Detect is ... |
H: Multi high input impedance chemical electrode buffer circuit
In What is the purpose of this op amp? you see my interested circuit.
Added:
The diagram above shows a single pH measurement "channel".
U1 sets a reference voltage of Vout_LM4140A/2, and U2 measures the voltage outut of the pH probe relative to the ... |
H: Radio interferes with I2C bus communication
I have a PCB with a Microchip PIC18F97J60 on it and every time I key a 5 watt radio transmitting at 144 Mhz next to the board it resets the processor. The processor resets when it’s attempting to communicate over the I2C bus. The watch dog timer times out waiting for the ... |
H: Antenna Length for Low Frequency Radio Signals - Why so long?
I know that when you want to pick up low frequency radio signals, the longer the wavelength, the longer the antenna needs to be. Why is that?
mj
AI: Think of the vibratory modes on a string clamped at both ends. When you clamp a length of string at bot... |
H: Does magnetism affect SD cards?
Would a strong magnet have any effect whatsoever on a thumb drive (I'm assuming not) or on an SD card? It seems unlikely, but I'm hoping someone can give me a definitive answer, since I'd rather not find out the hard way that it actually can. Assume the magnets are powerful industr... |
H: Confusion with negative voltages in this opamp circuit
I want to use a circuit like below to amplify a photodiode:
(taken from this page)
But it requires negative voltage.
Can I use the following circuit I modified instead with a positive supply only:
And if correct, how can I couple the output to an ADC input?
A... |
H: DOIT esp32 devkit v1 schematic confusion
I'm creating my own small dev board for the esp32 wroom module.
I'm following the schematics for the DOIT devkit v1 module.
Full schematic here: https://embedded-systems-design.github.io/overview-of-the-esp32-devkit-doit-v1/SchematicsforESP32.pdf
I'm unable to workout if I ... |
H: Control buzzer with GPIO
Edit: Realised Silly mistake, I have the emitter and collector swapped on my PCB :( sorry about that.
I'm trying to control a magnetic buzzer indicator using an STM32 MCU. I have the circuit below which although works the buzzer is extremely quiet. I have testes with a voltage meter that t... |
H: Low level voltage is changing on I2C bus when starting communication
The setup:
I plugged an STEVAL-MKI224V1 board (basic eval board for baro sensor) on a nucleo F411RE. Communication happens through i2c bus.
I added 4.7k pull-up resistors on SCL and SDA.
The wiring:
SDO to VDD (set i2c address)
CS to VDD to activ... |
H: 3 dB Power Divider Used as Power Combiner S Matrix Explanation
I'm trying to understand the operation of an ideal RF power combiner.
Below is the scattering matrix of such device. (i.e. Wilkinson Power Divider)
\$[S] = {\frac {-j}{\sqrt {2}}}{\begin{bmatrix} 0 & 1 & 1 \\1 & 0 & 0 \\ 1 & 0 & 0\end{bmatrix}}\$
I know... |
H: How do I handle a component with pin spacings smaller than the necessary trace width?
I'm designing a board using a TPS2113 power mux in a TTSOP package to deliver ~1A from plug power or a battery to my board. My calculated trace width for this current is 25-30 mil, however the pins of this component are spaced 25 ... |
H: What is the best way to turn off power to motor controller's H-bridge?
I am trying to figure out the best way to implement an emergency shutoff for the H-bridge of a motor controller:
My requirement is to turn off the 48V to the drain of the FET based off a signal which is either 28V (when the emergency signal is ... |
H: How should I interpret this DP3T switch diagram?
Which pins are the poles and how are they connected in the three positions of the following switch?
Datasheet for DP3T Switch (SLW-993515-2A-SMT-TR).
I'm just not sure how to read this schematic:
AI: It's hard to know why they wouldn't make this information very clea... |
H: TDA2822D speaker connection issue
This is the circuit from the datasheet TDA2822D.
I have a question regarding the connections near the 32/16 ohm headphone. Why the two terminals of the speakers are connected together to the ground. I tried to draw the circuit, do I connect the pin1 and pin2 to the ground?
AI: The... |
H: Is it safe to connect CR2032 cells in parallel?
As mentioned in the title, I would like to connect two CR2032 cells in parallel to increase their capacity. If they are slightly different voltages then won't the better battery "charge" the weaker battery until the voltages equalize? My batteries are non-rechargeabl... |
H: The output of ADC (AD7091R-5) is slowly rising with constant input
I have a circuit board with an AD7091R-5 analog to digital converter. I'm reading the output via I2C using a particle board (much like an Arduino.)
I'm reading the register for channel 0 and 1 as I intend, but there's a constant rise in the output o... |
H: Matching network for a radio
I’m trying to understand how the matching network functions on the radio side of a transmission line. As an example, here’s an excerpt from the Nordic nRF52840 DK schematics.
As I understand it, when the radio is receiving, matching network B transforms the antenna impedance to 50Ω to ... |
H: The complete circuit of this project
This circuit is a solar charge controller module Can you help me get the schematic and PCB of this circuit?
AI: There is a 8 pin IC and a 10 pin IC. You need to know what they do. I guess the 8 pin IC is a linear voltage regulator and the 10 pins IC is a battery charging monitor... |
H: What's the transfer function of this op-amp circuit?
I have to analyse this circuit to find the transfert function between the input e(t) and the output v(t). I already know how to proceed. First the voltage at each pin and then difference between theses pins should be 0. I will end up with what I am looking for.
... |
H: Cable shielding (best practices)
I am making a cable to connect two boards as shown in the image below:
The cable will be around 25 cm long and will be in an electrically noisy environment (consider 220 VAC house wiring lines touching it physically). Cable will have a PVC sleeve on top.
Both boards will be in a no... |
H: Accelerometer output mA/g; how to get to mV/g?
Using a Q-Flex QA2000-030 accelerometer that has output of current. It has a scale factor of 1.2 mA/g. If I want to get the output as 0.1 V/g-- how should I go about making the change? Would an op-amp current to voltage work to change the output? How do I introduce the... |
H: How to filter a noisy PWM signal without affecting rise and fall times
I need to read the frequency and duty cycle of a PWM signal that is expected at 88Hz. It is getting a lot of noise (during radiated immunity).
Before noise:
After noise injected:
What filter would you recommended to clean this signal without a... |
H: Unable to get my astable multi-vibrator working in LTspice
I'm trying to build a basic square wave oscillator using an astable vibrator made with an op-amp for my Intro to Circuits class.
Unfortunately, I cannot get LTspice to simulate the oscillations.
I've tried a good chunk of the op-amps available. I've also tr... |
H: If the chassis is at high potential and a human touches it, will he get shocked? The proposed circuit is for the cancellation of CM current
This circuit is compensating the potential difference between the chassis and motor so the bearing current or leakage current cannot flow from motor to chassis to ground.
If ... |
H: TPS65251_Formula Error?
According to the formula, R11 will be 20.1kOhm i.e., R11=((1.2-0.8)*40.2k)/0.8 -> 20.1kOhm.
The outcome of 80.4kOhm does seem to be correct but seems issue with the formula. What do you guys think?
Datasheet: https://www.ti.com/lit/ds/symlink/tps65251.pdf?ts=1700049617159&ref_url=https%253A... |
H: Piezo transducer as both microphone and speaker
I'm trying to find the best piezo transducer for my project, which is a Morse code sender and receiver.
Since a piezo transducer can both act as a speaker and a microphone, and I only send/receive at a very specific frequency (700 Hz), and I only send or receive (not ... |
H: How are simple functions done in commercial products?
In commercial products, here for example a Google Home or Alexa, how are simple functions implemented? Say I want to make an I/O system which uses Bluetooth but without using an Arduino. An Arduino is too powerful and expensive for turning an LED on and off. In ... |
H: PIR sensor circuit
I am designing a PIR sensor circuit to detect human movement. I am supposed to display movement using an oscilloscope (the response from this PIR sensor.)
I have used the following circuit but it does not show any response on the oscilloscope.
Is there anything that I need to add?
AI: As in the c... |
H: Why not put a crystal oscillator inside the microcontroller?
Why not put the crystal oscillator inside the MCU itself, rather than using an RC internal oscillator? I could think of the following possibilities but not sure if they are valid:
MCU manufacturer wants to keep a low price of their product. A crystal wil... |
H: PCB design for Renesas' DA7212 audio codec
I'm designing my very first PCB. I managed to route all my components and I'm stuck at the last footprint - DA7212 from Renesas:
Those balls are both incredibly tiny and packed dense. I'd need a manufacturer with a minim clearance <1 mil to route between the balls, or a v... |
H: ATtiny85 USB development board
I am working on a project and have a custom PCB for the project. I initially developed the PCB to mount a DIP-8 ATtiny85.
I then found the ATtiny85 is available in an SMD package, so I am thinking of changing the PCB to use the SMD version. But after I searched the local market in my... |
H: strange phase behavior RC low pass filter
I have a low pass RC filter (R=12Ohm, C = 22µF) Which is showing some strange behavior in the phase shift. The cutoff frequency is around 600Hz, as calculated.
But the phase shift goes to -45° only at 890Hz and than it starts ascending back to zero? Could this be due to ind... |
H: Line-out vs headphone-out impedance
I'm thinking about the example of two output jacks on the back of a computer, one for line out and one for headphones. I understand that the line out in generally an "unamplified" signal and is intended to be fed to an amplifier with a high input impedance, and the headphone outp... |
H: Why doesn't the LED shut off?
Why doesn't the LED doesn't shut off when I set the input to 0V? The simulation does, but that's not what happens in the real circuit. I've grounded the second op amp's inputs (on a NE5532), tried using the same 5V supply for the LED, checked, double checked and rechecked the circuit.... |
H: Why use resistor in series with coincell for RTC backup power?
I've noticed a lot of reference designs use a resistor in series with the coincell supplying power to a backup RTC. For example, see R141 on Varicite's sheet 8 of the schematic for the carrier board for their DART 8M SOM:
Why is this? Is it some sort o... |
H: Using capacitor with voltage rating close to input voltage
I am using a buck converter in my design. The input voltage is 12V and output voltage is 5V.
The capacitor C331 and C332 are 10 uF 25 V in 1210 package. The inventory have already 16 V 0805 capacitors. All these are ceramic capacitors (C331, C332 and caps p... |
H: Power bank or fire hazard?
I do have a bunch of 18650 LiPo cells, salvaged from various sources. Now, I happened to come across a variety of power bank cases on Amazon which mostly look like this:
Even a cursory look tells me that these are designed for 20 cells connected in parallel, without any individual cell b... |
H: Do Kirlian setups work with DC power?
I have been trying to build a simple Kirlian setup, and I've been trying to make my flyback transformer work, to no avail, so I shifted to use the small black 3.7 V to 400 kV transformers (as they like to advertise. I reckon they only give about a maximum of 50 kV, but they pa... |
H: Why does my flyback transformer simply refuse to work?
I've been trying to create a Kirlian setup like the one in a video by 'The Plasma Channel', and the flyback transformer for the power source just refuses to work.
I have a T1010A transformer, and I'm winding its core by hand. I have a IRFZ44N transistor to driv... |
H: How can I attenuate noise from synchronous divider and OCXO?
I am experimenting with a square OCXO, dividing its output frequency to 1kHz using a 4017 synchronous counter and feeding the output to a sound card using Spectrum Lab software. I can then record it and pass it to another software to visualize the output.... |
H: Split and mix audio signals
I need to feed input to an audio amplifier from an USB DAC. The audio amplifier has separated inputs for headphone and speaker but DAC has only one output (stereo). Moreover the speaker input is mono while the headphone input is stereo.
Since I don't know the input/output impedance level... |
H: Understanding ADC digital isolation to avoid ground loops
I have designed a circuit to measure the voltage of a battery. This battery is being cycled all the time by a potentiostat (charging-discharging) which injects positive current to charge the battery and negative to discharge it (and simultaneously it measure... |
H: Why is the opamp's inverting input not at virtual ground?
I've have been trying to make a current to voltage converter using a transimpedance amplifier circuit. I have been simulating the circuit in LTspice and everything seems fine, but when I built the circuit in real life it has shown a problem I don't understan... |
H: Can I use one 12 V 8 A power supply to provide 5 V 10.5 A power via buck converters?
I want to power four 5 V devices via a single 12 VDC 8 A (96 watt) supply using a buck converter for each device.
I know I could try and redo my circuit but this means disconnecting and rewiring just to test, so I wonder if someone... |
H: Can dielectric coated metal wire mesh in electrolyte be a capacitor
Since capacitance is proportional to the area of the plates, why don't we just make a mesh out of metal wire (plate #1) and coat it with a thin layer of dielectric material, then submerge this mesh into an electrolyte (plate #2) which is connected ... |
H: Hum without ground loop
I have an audio measurement system. The system is connected to and powered by a laptop. The system has no other connection to the AC grid. Now, if the laptop is connected to the AC grid and i measure an audio channel, the resulting digital signal contains a lot of humming. However, if I disc... |
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