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H: Possible causes for AAA battery to explode
Today, the AAA battery in my remote control exploded. The "pop" sound is pretty loud. I've been using this remote control for years, and I'm more inclined to believe that it is the battery issue rather than the circuit issue, because if it was the circuit problem, the prob... |
H: Can I use a potentiometer to reduce sound level in a speaker?
I want to reduce the level of sound in a speaker (i think 6Ω 30w rms). I wonder if it is that simple to put a potentiometer in one of the cables.
If this can do the trick, how do I calculate the resistance needed?
AI: That's a way, but it's better suited... |
H: Blind/buried vs. through hole vias?
I'm trying to learn PCB design and, from what I've read and seen, there appear to be three different types of vias:
Through hole - goes all the way through the board
Blind - goes from the top or bottom layer to some layer in between the top and bottom, but not all the way throug... |
H: Is this 7805-based design correct?
I found this design on internet:
It is said to be a regulated power supply with variable DC output 5-15 V, 400 mA. My first question: Is this design around 7805 correct? I am asking because it doesn't correspond to the the 7805 datasheet:
What I miss there is R1. I expect there ... |
H: Need help identifying a capacitor
I have a ceramic disc capacitor that got cooked in a power surge due to a faulty generator. The capacitor was between the fuse and transformer of a circuit board for a pellet stove.
It is RED with and though damaged, I can make out two lines of text
50L10
0933
I believe ... |
H: Calculating maximum wattage
If we get 220V from outlet, would it be possible to tell the maximum power (wattage)?
Since,
Power = Voltage (V) x Current (I)
Also, Is it possible to get the maximum amount from current (I) from 220V? Assuming any type of standard wire with resistance used?
AI: Assuming the wiring is ... |
H: How do I produce a linearly chirp signal in spice?
I want to produce a chirp signal to test my PLL and found out the lock range.
There is the PWL and pwlFile as Spice commands, but I can't understand how can I produce a linear chirp like this :
This is a Matlab function I have to build such a signal and a binary c... |
H: Oscilloscope/Function Generator with GnuRadio (using very cheap hardware)
I was just getting started with RF signal processing, and I was very interested in being able to make an oscilloscope and function generator work in real time with Python. Essentially, I would like some means of:
*Creating arbitrary waveforms... |
H: 12V relay circuit, converted to 5V relay, under uC control
Few questions about a little Home-Automation project I am trying.
Below is the schematic which I found in an article, slightly modified to suit the parts I have in hand --
Original had,
Q1 = BC548
Relay = 12V coil voltage
Mine has,
Q1 = BC547B
Relay = 5v c... |
H: How to transmit high current (2.6A) with low voltage (1.2V) for a long distance?
I want to supply a DSP with 1.2V. This DSP needs 2.6 Amps of current at full load. The minimum supply based on the electrical specs of this DSP is 1.16V, which means that the maximum voltage drop caused by power planes, traces and conn... |
H: How does electrical devices consume power?
I'm curious to know how does an electrical device can consume any amount of power it is required? Suppose the voltage here is 220V. How can you get any amount of electrical power say. 1000 watts out of it? Please tell me what I'm misunderstanding.
AI: The power line may be... |
H: RC Circuit with Multiple Capacitors
I have been working on this problem and it is driving me absolutely crazy. The questions is asking for Vo for time greater than or equal to 0. I have successfully redrawn the circuit (shown below) to represent steady state or t = (0-). This gives me an initial value at Vo of 12 v... |
H: Why does a cold solder joint appear grainy or dull?
A good solder connection is shiny, and we're taught that dull solder indicates a cold solder joint. Why is this?
AI: Sometimes you can see a difference in the appearance of the metal of a bad solder joint. I think this is due to something having gone wrong as th... |
H: Silicon Controlled Switches: applications&suppliers
I came across this description of what are called "silicon controlled switches." I always look to balance n/p-channel electronics for stability, and using these silicon controlled switches seemed like the perfect way to do so. However suppliers seem few and far be... |
H: Write back buffer in lpc
I was reading the Lpc2148 Manual and in the Static Ram section I came across
Write back buffer
The SRAM controller incorporates a write-back buffer in order to prevent CPU stalls
during back-to-back writes. The write-back buffer always holds the last data sent by
software to the SRAM. Th... |
H: Why does fuse blow up sometimes?
Sometimes once in a year, either one of main fuses or a fuse in room blow up due to something. What is the cause of this? Why do we even use fuses? Is it because the voltage doesn't stay at 220V all the time?
AI: IMPORTANT:
It is far far better that a fuse sometimes blows when ther... |
H: Why do rechargeable batteries have no short-curcuit protection?
Whenever I read a user manual to a device that runs off a rechargeable battery - like a cell phone or a power driver - the manual will always say I should store and handle the battery in such way that its terminals are not shorted by any objects like a... |
H: Driving LEDs with 74HC540 or 74HC541?
I have some LEDs (not the high power type) being driven by a 74HC541, one LED per output, with no other load. I've noticed a tendency for people to use the 74HC540 instead (inverting buffer). I've gone through the datasheets and both ICs can sink or source 25mA per output pin (... |
H: Are there any Analog FPGAs?
As I understand it FPGAs are flexible "digital" circuits, that let you design and build and rebuild a digital circuit.
It might sound naive or silly but I was wondering if there are FPGAs or other "flexible" technologies that also make analog components available to the designer, like ... |
H: Why can this 7-segment LED show 2 colors?
I have a 3-digit, 7-segment+decimal display I bought from an ebay store. I believe it is a hi-eff red one, and the seller provided this link to the data sheet. A search found this data sheet which is more complete and seems to describe the part better, though bottom line ... |
H: Which relay switches can be activated by the parallel port?
I'm planning on controlling some external circuits using the parallel port by switching on relays that can switch on the external circuits.
Am I right in thinking the pins have a voltage of 3-5V when high and a maximum current of 50mA? The most sensitive r... |
H: Are I/O pin internal resistances equal to the Thevenin resistance?
I'm trying to find the Thevenin resistance of an I/O pin for the ATmega644. I see on the datasheet that there is a 20-50 kohm range of internal pull-up resistance. So with that, I can create a circuit modeled thus (ignore all values):
The voltage s... |
H: NE555 load resistor?
I'm using 555 timer in astable mode. I've used Multisim to generate it ant this is what I've got:
I'm little confised by the 100 ohms Rl resistor. Do I need it there ? If I do, why ? I've tried with and without it, and it works for me both ways ... I'm using the 555 to drive another CMOS IC in... |
H: DC supply for control circuit of a DC-DC converter?
I have a switch mode DC-DC converter assignment which is supposed to convert 36-72V input DC voltage to 9V DC voltage. The circuit I'm working on contains a control circuit (implemented with a custom and multipurpose microcontroller) which requires 5V DC supply (a... |
H: Xbee Shield - Turning jumper settings into ON/OFF (XBEE/USB) manual switch
I have the following Xbee Shield where I need to constantly switch jumpers in order to allow Xbee communication and/or USB communication.
The following is set for Xbee communication:
"Xbee Communication"
The following is set for USB communi... |
H: Sequential Circuits
I'm learning about sequential circuits, and it's driving me crazy. How can you use an output as input, what was it's value at time 0? It can't go on forever...
AI: Generally, its input at time 0 is arbitrary unless a reset circuit of some kind forces it. You either have to have such a reset ci... |
H: Need help with board / components recommendation
I'm trying to make a self-contained graphic playing system, and would like to have components or full PCBs suggestions. What I need is:
Output to a small color LCD. Like 3 inches, 65K color, 640x480 for example. No touch screen. Can be smaller if that helps, but at ... |
H: TLC5940 and ADXL335 circuit 'glitches' on perfboard. Need decoupling caps?
I created a circuit containing one TLC5940 and one ADXL335 breakout board. The ADXL board comes configured with 0.1 uF capacitors to set the bandwidth of each axis to 50Hz.
It is wired to an Arduino Mega 2560 like this. The ground is shared ... |
H: Where can I get a small cheap linear actuator?
First, I should clarify: I am not looking for much power or much precision. I am looking for the cheapest thing I can plug into an arduino. I am just looking for stuff I can use for prototyping/proof-of-concepts.
I was taking apart an old CD drive when I noticed there ... |
H: What is the easiest way for me to measure the amount of "juice" that's left in an alkaline battery?
This question applies equally to both non-rechargeable batteries and rechargeable batteries.
I want to know if I managed to fully recharge my rechargeable batteries (mine are primitive), and how much battery life is ... |
H: Extending a pulse from a DTMF Decoder
I have built a DTMF decoder which offers relay closures corresponding to the digits received. Everything works great, except the equipment I am interfacing to is slow.
The office telephone system gives a pulse of tone whenever a digit on the telephone is held down. From what I'... |
H: A cheap experiment to demonstrate the relationship between resistivity and heat output
I'm trying to design a cheap experiment that will demonstrate relationship between resistivity and temperature change under current. Optimally I would
Find some relatively resistive substance
Run some current through it.
See how... |
H: Bias headphone audio signal for use with digital potentiometer?
I am attempting to control speaker volume via a digital potentiometer, the problem being that audio signal goes both above and below 0V, for regular potentiometers this is no problem but for digital they cannot handle a signal below ground.
How can I s... |
H: What's the point of Karnaugh maps?
You can't use them for more than 5 variables efficiently and no "real life" circuit has only 5 variables (except for the simplest of them). So what's the point of them? They seem pretty useless for actually engineering work.
AI: In today's world with many decent choices of hardwar... |
H: Do I use a 5V 2A or 3A DC adapter to power my 2m (6.5ft) WS2801 LED strip?
(Please excuse me if my English is bad)
I recently purchased a 5m LED strip, but I only need to power approximately 2m (6.5ft) of the 5050 RGB LED WS2801 strip, but I'm afraid that a DC power adapter with 2A may not provide enough current, o... |
H: What bluetooth chip / type should be used for a remote control car?
I am building a small remote control car to be controlled by bluetooth (iOS and Android). I am having a custom circuit board built, and I want to know what bluetooth chip I should get. I would like the range of the car to be at least 20-30 feet.
AI... |
H: Platinum RTD temperature sensor choices between 1000ohm and 100ohm
I heard the Platinum RTD temperature sensor are very accurate and I want to use it for my temperature measurement project (-40 degree to 80 degree range). I don't want to use other type sensors.
Platinum RTD sensor have 2 categories: 1000 ohm and 10... |
H: Compensating input impedance
I'm trying to measure the reverse leakage current of some diodes with the method proposed HERE - the diode is connected in reverse bias to 5V through 1 megaohm and voltage is measured across the resistor, the current is calculated from the voltage. However I need to do this as accuratel... |
H: 3.5mm headphone jack frequency range
I want to receive audio data from a device and handle it through the mobile’s headphone jack, but my data has a low frequency of about 1Hz. I’ve found that it’s too low for this port.
I’ve searched about the 3.5mm headphone jack frequency range but couldn’t find anything!
What i... |
H: What are the tradeoffs between control vs software algorithms (in charge pump PLL)?
I have a grid signal (45-65 Hz) that I've sampled with an ADC and put it through an IIR LPF so that noise does not effect the zero crossing detection.
All I want is the frequency of the signal. Now what are the advantages/disadvanta... |
H: Connection problem with RS485 system on PC with RS232 port
I am developing a system in which I have to integrate hardware. I am from computer background, so I don't have much knowledge about hardware systems.
The issue is I have to integrate with London based taximeter with MR400S model. This taximeter gives output... |
H: How to ON/OFF two fans with 3-state rocker switch?
I have a 3-state switch, It has 3 pins. It can have 3 state as you can see in the picture below. when it's off (i.e on O) the middle pin is not connected to anything! When it's on I, the middle pin is connected to I and when it's on II the middle pin is connected t... |
H: Relation between C-rate and power of a battery
I'm a non-engineer, but I need to understand the function of a battery. I hope you can help me!
For example, I have two bulk storages.
5MW (power) 5 MWh (capacity)
5MW/10 MWh
So the definition of the c-rate is: A C-rate is a measure of the rate at which a battery is ... |
H: How does part of a microprocessor (Apple secure enclave) use a microkernel (L4)?
Please excuse my ignorance. I'm an 'old-fashioned' guy who thinks that there is just 'software' and 'hardware' - and these are two separate things. Along this line of thinking an OS is part of the software, and a microkernel is part of... |
H: Headphone has no sound if fully inserted in jack
When I connect my headphone to headphone jack in my laptop, I don't hear any sound. Unless I do not fully plug it in and instead just plug it in around 50%.
Sometimes I hear sound but it is all garbled.
This headphone used to work fine before and now it is giving m... |
H: "Chip Select Bar" - proper jargon or a place to have some beers at?
Today, I came across a data sheet for an ADC (cf. p. 2) including a pin list with the "barred" (i.e. overlined) letters CS, indicating negative logic for the Chip Select pin, followed by the name that had the word "Bar" spelled out.:
\$\overline{CS... |
H: UART without using the same clock
I am using the C027 development board for prototyping an application and I was wondering it it was possible to use the Tx and Rx pins of the GSM module (available on the pinout of the board as P0_15 and P0_16) to communicate with another microcontroller on another board (like the M... |
H: Rogowski Coil High Frequency Limit
I'd like to do some experiments involving high frequency (1.296GHz to be exact) that involve an 50ohm inductor that has minimal RF losses. The obvious candidate is to drive a Rogowski coil (driven as though an air-core current transformer without a secondary running through the c... |
H: Efficient use of space in FPGA
Background and clarifications:
I've never developed/written a single piece of hardware before, but I'm currently using Verilog to develop a huge project for a FPGA as my final graduation project.
I've got some questions on how to write verilog code efficiently. (Assume that, when I s... |
H: How do I reset a capacitor once I have a signal rise?
Once the signal rises to a certain level, my capacitor starts getting charged.
Once the signal falls back down to that same level, my capacitor stops charging.
This way, I am using the voltage of my capacitor as an indication of how long the signal stays above ... |
H: Make outputs single ended on CS4234
I am working with the CS4234 codec for a project
It has 4 ADCs and 5DACs. One thing that is confusing me is that the pins are labled AOUT1- and AOUT1+ in the similar fashion for all ADCs and DACs.
The device states it can do single ended, which I believe is what I need to achi... |
H: Why does a Category 5 rated jack have different solder tail positions than a traditional jack?
I am attempting to specify a replacement part for a modular jack used in an original design (I basically need something that will stick out farther than the original). However, the part I would like to use specifies diff... |
H: Level vs edge triggering, usefulness of level triggering
Many processors / µCs / dev-platforms (BeagleBoard, Arduino,...) use interrupts.
These can be triggered by the detection of:
HIGH level
RISING edge
CHANGING level (either FALLING or RISING edge)
FALLING edge
LOW level
Now either of two things must be true: ... |
H: Displays, camera, speakers, microphones: why after more than 50 years of development do they still need calibration?
An old question running through my mind:
Displays, camera, speakers, microphones: why after more than 50 years of development do they still need calibration?
Whatever cheap or high-end material I com... |
H: Can I replace capacitor with multiple lower value capacitors in filter?
Can I replace higher capacitance value MLC capacitor in Sallen-Key topology filter with 2-3 lower value capacitors in parallel (with total capacitance equal to replaced cap)? I tried it in TINA-TI and AC Transfer characteristics are identical. ... |
H: Divisible-by-2 Circuit Help!
I'm having a little trouble with my boolean algebra and I was hoping you all can help me out. I've been given the task of designing a circuit that takes in a binary 4 digit number (X3X2X1X0) and returns '1' if the number entered was even. I'm fairly certain that my truth table is corr... |
H: Numerical value in decimal of the 32-bit word stored at address 1000H
I'm a little confused how to tackle these three questions.
Assuming two's complement arithmetic and operand alignment, give the numerical value in decimal of the 32-bit word stored at address 1000H and of each 16-bit half-word stored at addresse... |
H: Diode-connected transistor, small-signal, Norton, Thevenin
How do I calculate the equivalent Thevenin resistance of the small-signal model of a diode-connected transistor (base tied to collector)? Early-effect is neglected. The port of interest is between C and E.
In the figure, \$v_{\pi}\$ is the small-signal vol... |
H: What's the purpose of a ferrite bead inductor on this circuit?
I'm studying the analog voltage reference circuit described in the AVR450 Application Note - Battery Charger for SLA, NiCd, NiMH and Li-Ion Batteries, which schematic is below (copied from page 38).
On page 40, there's a schematic showing the MCU conne... |
H: Why is there a 0R resistor linking GND and AGND in analog voltage reference circuit?
This is related to another question I've just posted (What's the purpose of a ferrite bead inductor on this circuit?), regarding the battery charger described in the AVR450 Application Note - Battery Charger for SLA, NiCd, NiMH and... |
H: Charger light circuit
I have a charger light. It gets charged by 220V AC supply. It can light 5 LEDs. I know that it needs to make the supply 220V AC to DC of lower voltage nearly 5V to 10V. Then it can charge the small battery. But I found no transformer in the circuit. There are simply some diodes resistors and c... |
H: Writing down logic of a circuit
I have this circuit :
I'm trying to write down the logic of every output (W,X,Y,Z), to get a truth table out of it :
W = NOT (A OR B)
X = NOT A AND B
Y = A AND NOT B
Z = A AND B
But when compares to the source, my truth table is wrong, so I know that my logics are all wrong.
... |
H: Measuring the input impedance of an oscilloscope
I am measuring the voltage drop on a 1MΩ resistor with an oscilloscope, and as I understand to get accurate readings I should compensate the internal impedance of my measurement device for such a high value resistor.
It's a Tektronix TDS2024C oscilloscope, from the m... |
H: Why are these Fourier transform values not as expected?
We are being taught Fourier Transform in our EE course this semester and I have several questions about it. The answers do not need to be rigorous and mathematical, all I need is an intuitive 'feel' of the Fourier Transform. I may be completely wrong at certai... |
H: Using XR2206 function generator with split supply
I have an Exar XR2206 to generate triangle wave with single supply Vcc. This wave has peak value 12 volt and 0 volt.
How to make this IC operate in split-supply?
Hence I got triangle wave with peak value +6 Volt and -6 Volt.
AI: The XR2206 will operate just fine fro... |
H: What size crimp connector for 2.54mm headers?
I have a few pin headers on my board which are the standard 2.54mm spaced pins (datasheet), and I'm trying to find the appropriate female crimp connector which will connect to it, exactly like the one below:
However, I'm having trouble determining the size of the crimp... |
H: Powering a large DC motor from the mains
I scavenged a 220 volts DC motor from a large photocopy machine.
How can I best get a suitable 220 volts DC supply when our local main supply is 240 volts AC? Since the voltages are so close is there a cheap way to convert type of current on a one-to-one basis like this?
AI... |
H: Why is an op amp's bandwidth higher at lower gains?
If I build a resistor network where the op amp has a lower gain, it is able to maintain its gain for a larger bandwidth. Why?
AI: This is called constant gain-bandwidth product but it isn't true for every op amp. It is only true for voltage feedback op amps which ... |
H: Does a capacitor discharge itself when the charging voltage becomes 0?
I am charging my capacitor with a binary pulse train (either 1V or 0V). I notice that when the voltage stays at 0V, the capacitor discharges itself.
As shown, the green curve signal is connected to one terminal of the capacitor, and the blue cur... |
H: ISA efficiency code compaction and memory traffic
I'm having issues understanding this problem and am new to ISA's. Here's a problem with 3 questions and my biggest question is, what is supposed to happen? Specifically, the HLL Code at the bottom.
Assume four ISAs
accumulator-based
stack-based
memory-to-memory (o... |
H: Info on transformers? Where to find?
I'm quite often taking things apart to salvage the parts and use them in my projects. Right now I'm taking apart an old PC-power supply for a switch-mode lab-supply project.
The power-supply in question is Delta Electronics DPS-460DB A. Below is a picture of the transformer that... |
H: How do you determine graded versus abrupt diode junction types?
The problem
When a diode is reverse biased with 8V, it has a junction capacitance of 15pF.
When the reverse biased is increased to 12V, the capacitance drops to 13.05pF.
Find whether it's abrupt or graded junction.
The solution
The capacitance of abrup... |
H: How to get USART and USB-Serial working on the STM32F4Discovery Board?
I'm programming a STM32F407VG chip on the STM32F4Discovery board using CooCox CoIDE. I've stitched together a program based on some examples and tutorials I found online to get USART1 through pins PB6 and PB7, and USB-serial through the microus... |
H: Difference between a magnetic field sensor and a hall effect sensor
I can't understand the difference between a magnetic field sensor and a hall effect sensor, to me are both the same.
I have a voltage detector pen that I can use when I troubleshoot my house I believe it detects the electric field (magnetic), but t... |
H: Why do microcontrollers have so little RAM?
Maybe this is more of a perceptional problem, but it seems like microcontrollers have advanced by leaps and bounds in the last 20 years, in almost all regards, higher clock speed, more peripherals, easier debugging, 32-bit cores, etc...
It is still common to see RAM in th... |
H: What data format do audio cassettes use?
How do the sound pressure values correspond to the magnetic domains on the tape? Is the format analog or digital?
AI: It's analogue. A high-frequency 'bias' carrier has the incoming audio signal superimposed onto it, and the result is sent to the recording head, which is ju... |
H: Impedance mismatch
When I connect an oscilloscope to a function generator use both oscilloscope cable (one connect to the scope and one connect to the FG), I got 700mVpp when outputing a sine wave of 1Vpp and 10kHz.
But when I use the BNC cable connects to the FG, and the scope cable connect to the scope I got 2Vp... |
H: How to design a switch for my integrator?
I have an inverting integrator
that integrates the input signal (green) into the blue signal.
If I do nothing, the integrator output will go down and down and down... I don't want this. I want to reset my integrator back to ~9V when the second green pulse comes.
With some... |
H: 5-stage pipelined implementation (RISC) of a microprocessor
I'm trying to solve two questions about a RISC 5-staged pipeline that is not exactly like MIPS found here (everything is included in this post).
Consider the non-pipelined implementation of a simple processor that executes only
ALU instructions in the figu... |
H: Stepper motor driver differences?
I have recently used a H bridge to control a small stepper motor obtained from a DVD drive and now want to look into controlling something larger, for example large Nema 23 steppers. From reading online I found that H bridges cannot be used for controlling such a motor and instead ... |
H: Is it possible to measure acceleration in sports activities with an accelerometer
I've been trying to make a simple prototype capable of measuring a punch or a shot put throw with an accelerometer, but suddenly stopped working, and "locked" into a value, has I was testing it.
When I was testing it, even tho I tried... |
H: Difference in the datapath of Load Upper Immediate to Load Word in a 32 bit MIPS processor
For the MIPS insturction Load Word I have got the following Datapath:
How does the datapath for the Instruction Load Upper Immediate looks like?
AI: I had these pictures sitting around except for the red lines.
The two in... |
H: Determining whether piecewise function y[n] = {x[n] if n even, -x[n] if n odd} is time invariant
$$
y[n] =
\begin{cases}
x[n], & \text{if }n\text{ is even} \\
-x[n], & \text{if }n\text{ is odd}
\end{cases}
$$
My usual way of solving time invariance problems is to do this:
$$y[n-m] = x[n-m]$$
but I have no idea h... |
H: Industry standard ways of connecting boards / modules?
There are literally thousands of different types of connectors when I'm searching on a distributor such as element14, and I'm not sure what are the "standard" ways of connecting boards together.
Currently, when I need to connect two different boards together, I... |
H: Size of passives for active filter
I am working with the CS42436 codec, and in their datasheet, they have recommended values for components to be used in an active filter that takes the differential outputs from the DACs and converts them to a single-ended channel.
I have no problem with the values and what compon... |
H: An Explanation of CMOS Logic
While trying to understand CMOS Logic on Wikipedia for class, I came upon this paragraph which I can't quite wrap my head around on the duality of CMOS:
An important characteristic of a CMOS circuit is the duality that exists between its PMOS transistors and NMOS transistors. A CMOS ci... |
H: Clarification about FCC exemption for subassemblies
please kindly help me understand the "subassembly" exemption of the Part 15 certification requirements regarding intentional radiators. I want to produce and sell a MCU board which includes wireless communication features built-in. Obviously this board must be i... |
H: Assembler coding for ARM (Cortex-M0 and M3): is it possible/practical?
Unfortunately there are no questions on Stack regarding ARM and assembler at all.
My concern -- is time critical devices. Let's take for an example one of my AVR-based device (program compiled with GCC) which should do something up to INT0 inter... |
H: Do "blown" fluorescent lights still use electricity?
When a fluorescent light fixture goes out, it often flickers and then after a while stops shining altogether. When this happens and when it finally dies is the circuit broken and does it still use electricity?
I don't understand too much what exactly is spent or... |
H: What does short to ground mean? How to do that?
I've just started a simple project using raspberrypi and a capacitive touch sensors breakout board. I had a few problems using I2C, but after some time of research I managed to get stuck on one only... On one of the forums I found an answer that solved the same issue ... |
H: Jump start car from lithium ion laptop battery
Building the actual circuits is beyond me at this point, but I'm wondering if it's technically possible to jump start a car from the power contained in a large lithium-ion laptop battery.
For example, I have this laptop battery with the following specs:
11.1V 8.4Ah 94W... |
H: MOSFET Cell Balancing Circuit
I'm designing a simple cell balancing for charging LiPoFe4 cells in series. In order to prevent overcharging, when on of the cells reach the maximum charing voltage, the microcontroller will enable the mosfet, to bypass the current to the next cell.
Consider the following circuit, whe... |
H: Two conductors in a magnetic field, canceling each other's EMF?
If two conductors are in a changing magnetic field, oriented the same in the field, and they induced equal EMF's, can their wiring be oriented in a way that they can cancel each other's induced EMF?
So that that $$\epsilon_t= \epsilon_1 - \epsilon_2$$
... |
H: Prevent loss of Large Signal Voltage Gain at low Rload
Operational Amplifiers (opamps) have the tendency to drop their Large Signal Voltage Gain when the load is too low. This behaviour is usually described in the datasheet. Loads of 500 ohm and lower usually result in very low gain.
How can I prevent this loss of ... |
H: Sniffing twisted pair without interupt
Is it possible, with an oscilloscope, scalpel and a lot of patient, to open up a network cable (twisted pair), and sniff the traffic? All without interrupting the network traffic.
So;
Use the scalpel to get inside the cables, one by one.
Use the oscilloscope to find out which... |
H: Difference between TLC272CP and TLC272CDR
I was using an operational amplifier in my project from Texas Instruments. The series is TLC272. There are many different models. Could someone tell me the significance or the meaning of CP or CDR in different types of TLC272?
Can you please explain which one is better and ... |
H: Using a bottle of water as a resistor
Today, while drinking some water from a \$500mL\$ bottle, I started reading the info about the water and found out that the conductivity (\$\sigma\$) at \$25°\$C is \$147.9\mu S/cm\$. So it came to my attention that maybe I could calculate the resistance of the water bottle, fr... |
H: Sending Signals over a Coaxial Cable
Recently I've been trying to understand how multiple signals can travel along a coax cable. Indeed, I have already read "How are multiple signals propagated in a coaxial cable?", but it doesn't seem to be exactly the same question, nor is it specific enough, so please don't mark... |
H: Designing a stiff voltage source using an emitter follower
simulate this circuit – Schematic created using CircuitLab
I am new to electronics, and I am trying to do Exercise 2.2, page 67 of The Art of Electronics.
Use a follower with base driven from a voltage divider to provide a
stiff source of +5V from an av... |
H: Power an op amp when having only higher supplies
I have a +-24 V supply and I want to power an op amp. I initially tried an LM324 using a single +24V supply, but I then discovered that I want the op amp to be allowed to output negative voltages too (which the 324 can't). I could not find an op amp that can take e.g... |
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