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H: why are there unused vias in eagle design
I have this design I grabbed online, and when I load it up in eagle and run a DRC, it gives me a bunch of airwire errors on vias that appear to serve no function. Are they just ones the designer left on there and don't care about? Is there any other possible reason why they... |
H: Why don't ICs include bypass capacitors?
I'm a newbie to electronics, so apart from the obvious physical size issues there may be a clear reason as to why this is a dumb question, but if the general rule of thumb is to use a bypass capacitor for all ICs on a board, why not just build capacitors right into the compo... |
H: Sine Wave Generator Circuit - Bipolar
I have this sine wave generating circuit working. It is based on an application note from TI (http://www.ti.com/lit/wp/snoa839/snoa839.pdf).
we are driving an inductive sensor with a 2KHz sine wave, and right now I am putting a filter and amplifier to make the the generated sig... |
H: Led strip turning on dimly when touched
I have a 12V led strip connected to a (cheap) 12V 5A switching mode supply.
The supply is connected to a remote control switch.
The supply does not have earth connection (only neutral and live)
The supply have an European plug ( Live and neutral can be switched by turning the... |
H: Toggle between two colors in a common-cathode RGB LED using a SPST switch
I'm working on a switching circuit for a guitar amplifier that uses one DPDT relay which is powered by 12V DC supply. A SPST switch (panel mount or footswitch) will power the relay and switch to a second amplifier channel.
Is it possible to w... |
H: Does the Low State in NE555 go to GND?
Here is the first schematic that I created : .
The Vcc is at 5.1V and I a self made using the LM317, Works Fine.
When I checked the Output with the Multi-meter I use., I was getting a high state of around 3.9V(Which I guess was fair enough.), but the Low was was giving an out ... |
H: How would you size the transistors in this problem?
I know that whenever you have series transistors multiply the equivalent W/L of the inverter by the number of series transistors. In the parallel case W/L remains the same. I don't know how to apply those two rules to this problem. All of the examples I can find ... |
H: How to reliably switch a DC analog signal that can vary from 10mV to 12V, and 1mA to 100mA
Preface: I'm a Controls Engineer, not an EE.
I currently have a system that tests resistance through a Device Under Test using voltage drop. I am using 12 Phoneix Contact PLC-RSC relays to alter the test circuit to perform va... |
H: Did the cold front cause usability issues with the batteries in electric cars?
This may be more of a motor vehicle question, but since I'm asking about batteries, I think it may be more suited here.
As we know, electronics don't like the cold.
As we also know, last week was real cold.
Now, I've had my fair share o... |
H: Capacitor charging/discharging waveform confusion
This is the circuit:
At t=0s, switch is moved to position 1 and the time constant= 1ms
At t=10ms, switch is moved to position 2, it is assumed there is no leakage current
At t=20ms, switch is moved to position 3 and the time constant is 1.5ms
The waveforms of posit... |
H: Getting the Thévenin equivalent resistance for a max power problem
The given question :
I went on to get Rth by adding a voltage of 1v to control the dependent source from which I obtain the current in the branches and get the total current , as follow then later decide it by 1 since 1/I =v by ohms law to get Rth... |
H: Is it possible to power STM32 Nucleo Boards from a 3.7 Lithium Ion battery?
I have a Lithium Ion Battery that produces 3.7 volts and i would like to use it to power my STM32L476RG Nucleo board to collect data on the ADC and push the data to SD Card.
I understand that i can power the Nucleo from external 5 volts but... |
H: Impact of increased pad length in PCB
I was wondering why I cannot edit footprint of LED 1206 to take care of LED 0805 as well so that I can mount one of them depending on the availability. To do this, I have to increase the pad size of 1206 footprint on the inner side to give a clearance of around 1.2 mm between t... |
H: Electrical Charisteristics of PIC24FJ1024GB610
I am reading the Electrical characteristics of PIC24FJ1024GB610 from it's Datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/30010074e.pdf
(Page 419/468).
it mentions:
Maximum output current sunk by any I/O pin 25 mA
Maximum output current sourced by any I/... |
H: A basic question about the meaning of dB of an antenna radiation pattern
I know that dB is always a power ratio. And to obtain dB there must be a reference power or voltage measured with respect to another.
Below is an antenna pattern which shows a -3dB point for instance:
What does that mean literally? Can it be ... |
H: Why does re-seating the battery work to fix a device?
I have a wireless mouse that is powered by standard AA batteries. Periodically I will go to use the mouse and there's no response. Every time when this happens all I need to do is open up the mouse, re-seat the battery, and then everything works fine again. I wa... |
H: Embedded system task scheduling for data aquisition on a CAN network
I'm struggling with the concept of how to schedule my tasks.
My Setup:
STM32F103 hooked up on CAN. Taking measurements with a Lidar V3 module comms via I2C, then distributing that measurement on the CAN
Interrupt 1 is a 1ms timer interrupt to init... |
H: Depletion MOSFET inverter
I know that if both transistors in a CMOS inverter are enhancement then the output will be as shown in the figure:
But I wonder, what if one of them is enhancement and the other is depletion?
AI: If one transistor is of the depletion type, then that transistor will never switch off. That ... |
H: Uart for Atmega32
Can manchester encoding be implemented using UART?
If not what kind of modulation can I use, using UART on the Atmega32. I am making a Visible Light Comm system. If I use the UART as normal I get flickering of the LED, because there are long strings of zero's and one's. I want to use UART because ... |
H: How to introduce delay to a signal
I need to introduce a delay to the output of an astable, it needs to be in the order of 10 micro seconds.
I have read that optical cable is good for delays, which makes sense for small delays, but I have no access to optical cable for the project I am working on. The ideal solutio... |
H: Connecting a supply voltage from linear encoder to camera IO board with a current limiter
I have a TTL output from an incremental linear encoder which also supplies a 5V output at 140 mA. I would like to use this 5V output voltage to power a camera IO board with RS422 Interface which has a specification of 5V/50mA.... |
H: How do I calculate period of synchronous counter?
So how do I calculate maximum frequency if this values are given:
\$T_{Hold-ff}=0.2ns\$,
\$T_{Delay-ff}=2ns\$,
\$T_{Delay-nor}=0.3ns\$,\$T_{Delay-nand}=0.4ns\$,\$T_{Setup-ff}=0.5ns\$.
I thought about: \$T_{Delay-ff}=2ns\$+\$T_{Delay-nor}=0.3ns\$+\$T_{Setup-ff}=0.5n... |
H: How do I implement a communications interface to an Altera FPGA?
I have a DE1-SoC with some data coming in through an A-D Card.
After digital processing I want to transmit data to a host PC for records.
I'm trying to figure out the easiest way to go about this. I've never used the HSP side of this hardware before,... |
H: How to solve this. Multiple op amps circuits in series
The question is. What value for R1 is correct if we want the total power amplification to become 30 dB
My calculations. 30dB is amplification of 1000 times.
Last circuit got amp of 15/1,5=10 times. 1000/10=100
We therefor need amp of first circuit to be 100 ti... |
H: Gradually ramping voltage on button press
I have a circuit with a button and a motor. How would I make the motor gradually ramp up speed over 1-3 seconds when the button is pressed and gradually slow down over 0.5-1 seconds when the button is released, instead of the motor going full speed immediately? The circuit ... |
H: 2 x 8-channel multiplexers with with linked outputs
I have only one input to measure 16 channels, my intention is to use this circuit below based on the LTC1380 MULTIPLEXER:
The multiplexers have different addresses (AO A1). The output of both is linked to the same output buffer. Therein lies my confusion how to d... |
H: Replacements for mica capacitors?
I realize that there is along history to mica capacitors; however, I've been unable to determine if there any modern equivalents that have the same static electronic characteristics. The short list of types that seem like they'd have similar behavior and properties over time are si... |
H: Transient analysis with Laplace and nodal analysis error
Have the schematic:
Solving using MathCAD:
There is an error in my equations with nodal analysis but I can't find where? May anyone help me?
I also add the solution using approach of series RLC circuit:
But it seems to be A1 and A2 constant sign is incorre... |
H: Which particular transistor types represent triode and pentode vacuum tubes best?
If you encounter an old text which uses tubes instead of transistors, and if you are not familiar with the tubes, which one of the transistor from the following transistor tree would you think of to understand the circuit?
I sometime... |
H: Flatness vs Frequency parameter in RF zero bias detectors
I require the measurement of RF power from a port, and I am considering using a zero-bias RF detector in order the measure the power being delivered through the port.
These devices give a voltage output which is roughly linear to the logarithm of the power ... |
H: Fan PWM driver - design question
I've been working on crating a simple PWM fan driver for my Raspberry Pi. To simply explain idea - I get 3 pin input (1 - PWM, 2 - 5V, 3 - GND), then using RC filter I turn PWM signal into voltage and feed it into positive side of OpAmp. Then output drives MOSFET which in turn works... |
H: Replacement of Tantalum Capacitor
We are using some tantalum capacitors for some products. for two purpose:
Bulk Capacitor
Low ESR for MCU power
Recently, we are suffering to get tantalum capacitors. Our supplier is saying that Chinese electric vehicle companies are using huge amount of these. So it makes the sho... |
H: Does changing wire gauge change output of a thermocouple?
So I've been experimenting creating thermocouples with copper and constantan wire, just by twisting them together at one end and heating the junction with a candle and using a voltmeter to measure the emf at the other end. I thought that changing the gauge o... |
H: Burned ST LINK by connecting it to the board
I have a PCB that is getting powered from mains and is connected to a Hi Link component (HLK-5M05 with 5V output). At the moment it is connected to an extensions with a button, a little bit like this one. When I power it on and start measuring I get the 5V output, 3v3 ou... |
H: Which diff eq is used in electronic engineering?
Its a projectthat our teacher gave us . To find which diff eq is used in this field .please help me.
(By diff eq i mean the diff eq like legendre or riccati that are famous and known by a special name )
AI: Assuming your only components are
resistors (V-I-relations... |
H: Latching relay not working
I'm pretty new to electronics. I've however recently used mechanical and solid state relays successfully. Now, I am just started trying to use latching relays. I am currently trying to create a set up whereby my raspberry pi would trigger the latching relay to both set and reset positions... |
H: Can i connect something else to programming pins in STM32 (SWD)?
As in the topic: Can i connect something else to programming pins in STM32 (SWD)?
For example a single LED with current limiting resistor connected to SWDIO and SWCLK pins. Will this load affect programming via this interface (SWD)? Should I use a buf... |
H: Size of a non-plated throughole (NPTH) for a spacer
I am designing a PCB. For spacer, I would like to use this part:
http://www.keyelco.com/product-pdf.cfm?p=4805
The diameter of this spacer is 0.25 inches.
What should be the size of hole on the PCB? should I use the same dia 0.25 inches for the NPTH holes?
AI: Th... |
H: Calculate electromagnetic torque of synchronous motor?
I usually use this formula $$P=Tω=Τ\frac{2π}{60}n$$
where n is revolutions per minute and P is the power depending on the occasion.
Since we have to deal with a synchronous motor we have to use the synchronous speed Ns. My big problem is what power should I u... |
H: Sensitive photosensor
I'm looking for an extremely sensitive photosensor. I have a setup where a beam of light of some sort (weak laser, or something else) will be shining into the photosensor. Every now and then, a molecule with a diameter of about 1.0 - 1.3 nanometers will pass between the light source and the ph... |
H: Current source driving capacitor in LTspice
A circuit is given (see the figure).
simulate this circuit – Schematic created using CircuitLab
where
$$I= \left\{\begin{matrix}
0, & t < 0\\
I_0 sin(\omega t), & t \geqslant 0
\end{matrix}\right.
$$
and the capacitor stores no energy at \$t = 0\$
So, the capacitor vo... |
H: Compute loss/inch for (differential) T-line from s-parameters?
I have the 4-port s-parameters of 2 PCB boards, where each board consists of a differential transmission-line with SMA connectors on either end.
The only difference between the boards is their trace length is different.
Can I accurately compute the in... |
H: USB plug in detection for charging port
Is there a way to detect if there is a USB cable physically inserted into a USB receptacle, even if it is just a cable (with nothing attached to it).
I am designing a USB charging port (short D+ and D- together styles) and would like to be able to disable the buck converter i... |
H: Which STM32 is best for logging a CAN network?
I would like to build a project based on STM32 that interfaces with a CAN network. The CAN network has a 250 kbit/s baud rate.
On this network I have to:
Log messages from 127 nodes with IDs between 0x381 and 0x3FF (each node transmits one message per second).
Transmi... |
H: full wave rectifier resistor place
Where is the best to place resistor in full wave rectifier circuit?
What is the difference in usage of the resistors in these two
circuits?
(values are not precise)
Three side questions:
what about removing one resistor and replacing the left one with bigger value in the first ... |
H: Bus isolation circuit
I got a question about BUS isolation circuits.
Is this a correct design?
Looks not to me.
The book said that if POWOK is high, two SMBUS will connect together.
But I think it's wrong, the NMOS should be turned on when POWOK is low.....
The other circuits is like shown below.
I think its purpo... |
H: How does this IF alignment procedure work?
Simple question (I hope!) I've been looking at AM radio alignment techniques recently and IF alignment in particular. The "generic" approach in a valve(tube) radio is to feed the IF frequency into the control grid of the mixer/frequency changer valve and monitor for peak... |
H: How to distinguish between Thermistor, Varistor and disk capacitor?
How to distinguish between Thermistor, Varistor and disk capacitor they usually look the same.
Is there any way to distinguish between the three? What are some ways I could do that?
AI: APPEARANCE
Start by visiting Google Images (images.google.com... |
H: I2C Slave address
What is the best way to discover if the I2C slave address is given in the 8bit or 7bit format in datasheet?
As I can see from programming guide for ADV7511 page 16:
The SDA/SCL programming address for the Main Register Map is 0x72 or 0x7A,
based on whether PD/AD is pulled high (10KΩ resistor to po... |
H: EAGLE PCB Delete all nets in a selected area
I have a section in my schematic which is full of shenanigans. I want to delete all the nets in the selected box with a single command. Is it possible? I mean only delete nets and not anything else:
If I have to do it manually I have to click 1 million times.
AI: Due t... |
H: Snubber circuit
The circuit is a Single phase motor(120V runs 4.7amps running amps), and a relay to trigger the motor on/off.
I'm looking to use a snubber circuit to protect the relay contacts for prolonged use. The motor shouldn't be switching on/off very often but to be safe.
According to this page:
http://www... |
H: How to identify the loops to apply Kirchhoff's voltage law in these circuits?
Here is what I know so far regarding KVL. To apply KVL to a circuit, the nodes of the circuit must be identified. Then we identify loops in the circuit (a loop starts at a node, travels along one or more branches and ends at the start nod... |
H: What is the tolerance level of SMD resistors?
As in normal ceramic and carbon film resistors we can calculate by color codes but nothing mention over the smd components so how to get it? As nothing is ideal so I believe there will be some tolerance level in it also.
please help :)
AI: You can't tell without the dat... |
H: Correct definition of transition in line coding
Hello I have following question and it says:
I basically cannot understand this solution.
My questions:
isn't it a sequence of 4 0s followed by 4 1s? (answer says 4 1s followed by 4 0s) since retangle below the middle line represent 0 in NRZ?
if you see the middle o... |
H: LED Lighting PWM Dimming (LM3404)
The LM3404 is a "Constant Current Buck Regulator for Driving High Power LEDs." One of the features the datasheet boasts is "LED dimming using pulse width modulation (PWM)." My question is, using this chip (and its associated support ciruitry), which of the following accurately refl... |
H: How to represent binary for differential and Manchester coding?
I have some questions with solution provided from random material, but I can't understand well.
Question 1:
I tried to represent binary for each block according to description in the picture above, is this correct? (where you see "? 1 1 1 0 0 0 0 ?") ... |
H: How to increase current output of an electromagnet controller?
I am modifying a Grove electromagnet controller (schematic below) to output more current with the same inputs. The controller unmodified takes in a 5V power input and a signal of 0-5V with 0-20mA. The output is 0-5V with 0-400mA. So its basically a curr... |
H: Current kills, but is voltage important?
We always say that a low current can kill. However my knowledge of current is the amount of Coulomb. When that is explained, there is no mention of voltage level...
However, shouldn't voltage be important too? Do we consider a voltage of 120V because this is the voltage in c... |
H: Turn-on resistance - IGBTs
I would like to find out the internal resistance Ron of this IGBT device :
http://www.infineon.com/dgdl/Infineon-IHW50N65R5-DS-v02_04-EN.pdf?fileId=5546d461464245d30146ae23713f0115
The Ron resistance is not included in the datasheet.
Is there a way to export Ron from the charts that are ... |
H: Charging 6 NiMH batteries in series via solar
I'm currently working on a project in which a Atmega328 is powered by 6AA NiMH batteries in series (7.5v, 2000MaH). It is in sleep mode most of the time, except to turn a servo a couple times a day, for a couple of seconds (Hence the need for the high voltage).
I have a... |
H: X-acto knife with soldering iron (Durable?)
I know many people who like to use an x-acto knife on their soldering iron. They use it to cut through plastic enclosures for their products. But the question is, how long will the x-acto knife last with the heat?
AI: Given that the blade is made from Steel, and Steel m... |
H: What is the use of 'import' in SystemVerilog?
Once a package is included, the file is compiled. Then why it is required to import the same package?
AI: There is an interesting article here regarding the difference between import and `include when it comes to packages. I'm going to attempt to summarise it here.
When... |
H: CAN bus signal integrity
The channels are CAN_H (red), CAN_L (blue), and CAN_H-CAN_L (brown).
It can be observed in the diagram below that CAN_H-CAN_L has an acceptable signal shape. However, both CAN_H and CAN_L look poorly to me. And actually the device is not running in a noisy environment. I have two questions:... |
H: where can I found STM32L4 DSP and standard peripherals library?
I want to use standard peripherals library for stm32l476rg(stm32-nucleo). But I could not find it. I dont want to use HAL Library. Do you any suggestion?
AI: ST doesn't have a "standard perhiperals library" for L4 as they used to have for other chips, ... |
H: Are flags strictly related to interrupts or not?
If we want to some flag to be set when true (for example FIFO is full), does that mean that we have to enable the interrupts?
Whether it will be set if interrupts are not enabled?
Are that flags always triggered, but it is on us to chose the way how we want to handl... |
H: How to interface AMBE-4020 vocoder chip to Ti CC2640R2F Microcontroller?
How to interface AMBE-4020 vocoder chip to Ti CC2640R2F Microcontroller?
The user manual of AMBE-4020 has not given any detail about this.
AI: The general procedure for connecting another chip to a microcontroller is:
Read the microcontroller... |
H: PCB design, Ground plane and power plane issues
This is the first time I am designing a 4 layer PCB. The circuit will work on multiple frequencies: Signal acquisition part works on few Hz to 200 Hz(max), but one portion of the circuit will generate 13.56MHz. Power supply is 3.3V from a Lipo battery. I am planning t... |
H: Optimal design choices for mosfet driver for DC-DC step-down converter
I'm dealing with an application in which a DC-DC converter is used to transform an input voltage of 15V DC into lower voltages.
The current configuration makes use of an LM27222 with two mosfets in push-pull configuration. The output voltage is ... |
H: Where does the power supply current return?
I am a bit confused about return currents on a ground plane. I try explain it based on drawing. Let be a PCB with ground plane that is powered by external power supply through a connector. An LDO regulates appropriate voltage for component on board.
Does the current of t... |
H: Why would electrons cross a cross section when there is no potential difference?
There is a cross section , it's said that electrons move from left to right and vice versa, and the total sum of the electrons crossing this section from left to right is equal to the ones crossing from right to left.
When we have pote... |
H: Are oil-filled transformers ever run at a vacuum?
Larger oil-filled transformers are sometimes dehydrated by removing the oil and pulling a vacuum inside the chassis for an extended time. That requires that the chassis must be rated to hold a vacuum. If I read correctly, the dielectric strength of a vacuum is great... |
H: LDO Regulator TPS737xx, connecting Enable to VIN and avoid damage when removing VIN
I'm designing a PCB that is powered by this solar charger using a 3.7V LiPo battery (maybe I'll have to move up to a 4.2 battery). I want to regulate that voltage to 3.3V for feeding a microcontroller and I've selected a TPS73633DBV... |
H: How does the Miller effect affect a JFET-amplifier stage with tuned-circuit input?
I'm trying to build a simple JFET amplifier of MW signals (500kHz-1.5MHz) using a ferrite antenna and a variable capacitor to tune the desired station. The schematics is pretty obvious, as seen in the following figure:
While designi... |
H: PIC16F877A PORTA RA4 not working as ouput
I have used RB state change interruption to turn on two LED connected to portA (pin4 and 5). The probem is when interruption occurs LED on pin5 turn on, but not LED on pin4. When I change pin4 to pin3 it works normally, but I can't use this pin, because my circuit is alread... |
H: busted WS2811 LED strip by overpowering, totally useless now?
Powered a 5V WS2811 LED strip with 12V by accident. It turned on for a split second, it fried a microcontroller, I noticed the smell and turned everything off as fast as I could.
When i tried powering the LED strip again with 5V (also exchanging for a n... |
H: Repurpose a MagSafe 2 Charger for USB-C
Hi Mac Owner here that is now dealing with cable hell...
I have an inexpensive 60W MagSafe 2 charger that I was wondering if I was able to rewire the connector for USB-C. I have experience with electronics from a repair stand point, but almost zero electrical theory.
Is this ... |
H: Audio amplifier provides the capability to drive 660Ω loads directly without buffering
From PGA2311 datasheet we can read this sentence.
Does that mean if I drive a 660ohm load at power P, in order to drive a 100ohm load with same power, PGA2311 won't be able to source enough current? So a buffer is needed?
How can... |
H: Butterworth filter with non arbitrary component
How do I design a filter with certain cutoff frequency and as flat pass-band as possible, given that:
one of the filter components is non arbitrary, and
that filter component does not match the corresponding Butterworth prototype (i.e., the impedance conditions and ... |
H: What is the difference or relation between Rd and Rf in a diode?
For the small signal impedance of a forward diode we usually write:
$$r_d = \frac{n\cdot V_T}{I_D}$$
However, in datasheets one usually finds a specified forward resistance: \$r_f\$
Can anyone explain the difference and or relation between the two?
A... |
H: Arduino Controllable Digital Pot for Motor Controller
I have an analog motor controller that has a B10K potentiometer on it. I'd like to be able to swap out the analog potentiometer for a digital one, but I'm not exactly sure what voltage is being sent to the original potentiometer as I don't have the spec sheets f... |
H: Mbed LPC1768 Too Slow for Virtual Methods
I've written an OOP program which calculates the position of an object following a Trapezoidal motion trajectory - accelerate up to max speed, coast until decel point, decelerate to target position.
The trajectory code is based around a state machine using virtual methods.
... |
H: Possible to run MCP2003 on 3.3v?
I'm planning on connecting a MCP2003 to a ESP8266.
The voltage levels of the uart (and any io) on the ESP8266 is 3.3v.
As far as I understand the datasheet, the MCP2003 needs to be powered by 6-30v, and it's io (out) levels on the uart side match the power voltage.
So:
Is it common... |
H: Reset circuit for D-flip flop?
I need to capture the posedge of a signal (ONSWA) and output another signal (PSHOLD) high until I see another posedge of ONSWA. My solution is to use a DFF with an inverted output with ONSWA as the clock and D <= !Q. Now my question is how to properly ensure this circuit is reset when... |
H: -5V to 5V DAC Design
I am trying to design a 10 bit DAC using an R-2R ladder. I hope to achieve a signal that can vary from -5V to 5V.
In the circuit provided, I am showing my design for 5 inputs. I have used Mosfets instead of directly connecting the MCU I/O pins to the DAC because their resistance varies a lot wi... |
H: Calculating CRC for bootloader firmware
I am using PIC32MZ2048EFH064, MPLABx3.40, XC32 V1.42, Harmony V2.01b. And my PC app is using MS Visual C++ 2010 Express.
Instead of using microchip's Pic32 downloader I want to build my own downloader and, I want to download my custom encrypted firmware using PC host applic... |
H: USB 3.0 RX&TX Connection
Sorry for the inexperience. This will be quick.
I have two Texas Instrument ICs, one is a device, the other is a hub.
I'm looking at a USB 3.0 device that has the TX and RX lines. When connecting directly to the hub, I should be switching those lines right?
TX (Device) <--> RX (Hub)
RX (Dev... |
H: Need help adding gain overdrive/control to my tube guitar amp design
I'm new to analog electronics, so bear with me. Consider my guitar amp design:
What we have is a 12AX7 feeding into a cathode follower, going into a James tonestack, through another 12AX7 gain phase, then through another cathode follower.
So I'm... |
H: Rectifier for two phases (220 V 50 Hz)
I have a switch circuit which works with two phases. I need a flyback SMPS power supply for my logic circuit. I want my control circuit to be alive if any or both phases are receiving power. This can be achieved if my bulk DC capacitor receives power from both phases simultane... |
H: Will placing a strong magnet near my electric skateboard Li-Ion Battery pack damage or discharge it?
The original clips securing my battery cover are broken and i thought of devising an alternate way to keep the cover shut involving a hard drive magnet and a hinge
the battery pack would sit in proximity (3-5 cm awa... |
H: 74181 ALU not working properly cascaded to add 8 bit numbers
I'm trying to make a homebrew CPU but having problems with the 74LS181 ALU, which I'm simulating in Logisim software before diving into real ICs and breadboards.
I've cascaded two 74181 following instructions found in many sites such as this.
This works f... |
H: Why are there two diodes in series in this test circuit?
Look at Figure 2 in the following datasheet:
http://www.onsemi.com/pub/Collateral/MMBT3904LT1-D.PDF
Why are there two diodes and not just one?
Thanks.
AI: The circuit includes two diodes to set the negative bias at the base during the turn-off phase of the m... |
H: Maximum power transfer for unknown resistance
simulate this circuit – Schematic created using CircuitLab
Hi,
I am trying to find out what should be the value of resistor connected across node 'ab' for maximum power transfer. So far I have tried working out by hand and I don't think I have got the right values. I h... |
H: Track vs sample-and-hold
This is the output of both track-and-hold and sample-and-hold.
But when I searched for its circuit I am getting the circuit I have shown below for both.
So my question is: if the circuit for sample-and-hold and track-and-hold are the same then how is the difference between the two getting... |
H: Should it be expected that some shielded wire is not good at data transmission?
I have recently purchased a reel of this specification screened wire from RS Components to use in I2C communications, expecting it to be very well suited to purpose. I am running at approximately 400 kHz clock on the wire and did not th... |
H: Electrical System Harmonics
I'm a mechanical engineer so I don't know much about electric circuits and power generation to begin with. Can somebody explain what a harmonic is in the power grid and what is the reason why it is bad? I understand it comes from non-linear electric loads but what does that mean?
AI: A p... |
H: RLC voltage at resonance
I did a small simulation for a RLC circuit as here :
How does one compute the maximal voltage attained for this resonance?
AI: At resonance, the final voltage on the resistor is precisely what the input sinewave amplitude is. This is because inductive and capacitive reactances totally canc... |
H: How does the IC design process work?
Particularly for highly complex, digital ICs. Is it bottom up or top down? In particular, for top-down design designs the actual logic gates?
AI: Actual logic gates are designed at manufacturer's foundry. They design various gates and other logic elements within their node capab... |
H: building a minimalistic rf circuit (as simple as possible just for OOK)
I have been recently interrested in rf transmission. I would like to create a small circuit to generate à 125kHz signal at about 10-15 meters. I am very newbie for these kind of things. When I look on the internet for some schematics they all s... |
H: Antenna concept, is it a passive device but how about gain?
Cisco antenna explanation
Here it says that antenna is passive device which doesn't offer any added power to the signal. But at same time it says that antenna is responsible for increasing the amount of energy to a radio frequency (RF) signal.
So I don't... |
H: Combined series and parallel resistors -- adding resistors
Sorry for the poorly worded question, I wasn't sure how to make it clear
If I have a 100ohm resistor with two 100ohm resistors coming off of it (in parallel), is the total resistance 200ohms?
simulate this circuit – Schematic created using CircuitLab
AI: I... |
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