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H: Inrush current limiter - design questions/review
I am considering to use the inrush current limiting circuit that was suggested in this answer.
I have a pretty big capacitive load of about 40000uF to charge. Its a buffer for a GSM modem that needs to continue running for several seconds after a power failure. The p... |
H: Why aren't the points to the left and right of \$R_1\$ and \$R_2\$, respectively, nodes?
What I don't get is by the definition of a node -- a point where two or more circuit elements join -- it appears that the dots to the left and right of \$R_1\$ and \$R_2\$ are nodes; both of those points join the dependent vol... |
H: Why is HV kept open in OC test of transformer?
Why is HV kept open in OC test of transformer? Also, why is LV shorted in SC test of the transformer? (Generally this is preferred - why?)
AI: By definition, an OC test of a transformer is an Open Circuit test. Why would you connect the HV windings? The open circuit ... |
H: Photocoupler interface
I found a CNA1011K photocoupler laying around and I wish to try it out. Could someone explain what the parameters from the datasheet mean and how to use them for particular circuit parameters?
LED maximum current If: 50mA - that's understood. How about the voltage across it? Standard LEDs ha... |
H: How to wire a RCBO/GFCI correctly (in series with the upstream RCBO/GFCI)?
For one of my projects, I need to add a RCBO/GFCI for the protection of the users. I know that there is a RCBO somewhere up the chain, therefore I am facing a confusion: there is a non-zero resistance between Earths which can be very similar... |
H: Diy inductor saturation current
I have a boost converter that will convert 12V and 11A to around 20V and 6A. Since I didn't find any inductors (in my local stores) capable of such currents and frequencies and the correct inductance I decided to build one myself.
I've calculated the required inductances to be around... |
H: The best way to trim a wheatstone bridge digitally?
I am building a Wheatstone bridge for strain gauge measurement. Due to component deviations a wheatstone bridge will often show an offset which needs to be trimmed:
If we assume that we're using 5% resistors, the worst case would be that R1=950ohm and R2=1050ohm... |
H: How hot do High Power 1-3W LEDs get
I'm thinking of Using 3W RGB high power LEDs for a project. I will only have one color on at a time so I'm pretty sure that it would be 1W of ussage at a time. (please correct me if I'm wrong) My question is how hot do they get? I'm planing to use heat sink but trying to gauge if... |
H: What Type of cable is this?
I know someone who needs a longer version (12ft) of this cable for their TV, but I do not know what type it is. Can someone please identify the ends for me so I know what to shop for?
The cable is has this written on it:
LWC 20-CMR-SD HDTV SERIAL DIGITAL 20 AWG CMR(UL) C(UL) E113333 ER2... |
H: How do I find the row and collumn sections enabled in an SRAM when the input address is th e binary equivalent of 1770 hex .
This is the actual quesion:
A 16K x 8 SRAM uses coincident decoding. Determine the row and column selection lines that are enabled when the input address is the binary equivalent of 1770(hex... |
H: What type/topology of SMPS is this?
I'm researching designs for a simple bipolar output switching power supply and came across the design below in a ST datasheet for the MC34063A.
However, there isn't enough information in the datasheet for me to implement this design and I couldn't find any SMPS topologies in oth... |
H: How to shield for electromagnetic interference (DIY level)?
I am building an optical rotation encoder for my "autonomous robot" (a LED pointing to a photodiode that gets interrupted as the axis rotates).
My issue is that at the voltage that I am using the motors (~9v) they generate too much electromagnetic interfe... |
H: Why does switch change parallel current after junction?
This is an image demonstrating the use of a pull up resistor.
I've just started studying electronics and have been learning about ohm's law. Ohm's law says that current within a circuit is equal to the potential drop across that circuit (or section of circuit... |
H: ADC value conversion
I am getting full scale ADC value from 0 to 16348. I am trying to convert it to 4-20mA and then to 0-25 bar pressure, as I am ultimately measuring pressure.
I am using the y = mx+c equation but failing miserably. Can any one please guide so that I can learn something.
I am trying something like... |
H: How to create ground and vcc pins
I try to create a GND pin and a VCC pin to connect them to a battery. On my eagle pcb I haven't found them. They should be like 5mm x 5mm.
On the schematic I added a ground and vcc pin, but I can't found them on the pcb.
I need a place (copper) to solder the battery connectors.
Is... |
H: STM32 USB CDC: How to stop device transmitting via USB when not connected
After over 3 weeks of testing and debugging, I have finally got my STM32 transmitting data reliably over USB. The problem is it NEEDS an application on the other side of the USB to consume the data. When connected to my PC, and a program disp... |
H: Can someone explain how this transistor comparator works?
I am looking to make a comparator using transistors and I stumble across this circuit claiming to be one:
Unfortunately, the description that came along with it leaves a lot to be desired, referencing components and points that aren't actually here - I assu... |
H: Why is PWM used to control LEDs even when they're only used On or Off?
I've noticed on cars with LED tail lights that they have a flicker to them - I presume because they're PWM controlled.
But I've seen it on vehicles where brake lights and tail lights are separate luminaires, therefore are just on or off and do n... |
H: Driving proportional valves from microcontroller
I am looking to drive a current regulated proportional (solenoid) valve that needs up to 85mA @ 24V from a microcontroller.
So far I found this circuit that looks pretty straightforward:
What are other low cost options? Is there such a thing as a programmable curren... |
H: Reverse Engineering: TTL/LVTTL signal direction
I just ordered my first scope (a Rigol DS1054Z) and have been thinking about some interesting experiments/learning projects to perform with it. Thus far most of my experience has been in building circuits/MCU + FPGA programming.
One thing I'd like to try to play aroun... |
H: Op Amp saturating below supply voltage?
I would like to know why op-amps saturate below their supply voltage. For instance I have a circuit with an LM358-N amplifier IC that is powered at +5 [V] and connected to ground on the other rail. Theoretically the saturation should be 5 [V] but it saturates actually at 3.7 ... |
H: Timing circuit with op amps and capacitors
I understand how a basic comparator op amp works and how a capacitor charges individually, but I can't seem to put it all together to make this circuit. I think I might be messing up with the voltage rails and grounds somehow. The point of the circuit is for the LEDs to li... |
H: switching regulator feedback resistor
I was reading the datasheet of a switching powersupply RT8251. In the layout recommendations there is a statement -" Connect feedback network behind the output capacitors.
Keep the loop area small. Place the feedback
components near the RT8251"
What does it mean by behind outpu... |
H: What (if any) is the leakage current through a NPN (C-E)?
So I have a circuit where I need the current consumption to be low. Therefore I am using a 10M\$\Omega\$ resistor to 'pull-up' the pin on a chip which will need to be switched between high and ground (by high I mean the supply voltage which is ~3V).
In orde... |
H: how to resolve LM358's huge error as a current sense differential amplifier
I've built a current sense differential amplifier that measures the voltage across a 1 Ohm resistor, to give me a reading for the current through it.
I've connected it as follows, all resistors are matched 10k to give a gain of 1:
(Image s... |
H: Supply microcontroller and solenoid with the same battery at different voltage levels
I'm working with a microcontroller which its supply voltage range is 1.8V to 3.6V
I want to connect a solenoid to this mcu (this solenoid will be activated occasionally).
Current–voltage characteristic of the solenoid:
Input vol... |
H: Spiral Core Transformer
Presently, I am reading about different types of transformer. I am stuck on 'spiral core or wound core transformer'. I didn't find any good explanation about it in the textbook I am reading. Searched on the internet in hope to find more detail, but same thing, no good description.
I am provi... |
H: How do I solve this circuit using nodal analysis?
Hey guys I cannot wrap my head around this damn circuit and how I'm supposed to solve it using nodal analysis. I chose the bottom node as my reference node and I got to these equations:
Node A is the left one, node B is the middle one, node C is the right one and th... |
H: Acquiring and fusing data from different controllers
TL;DR: What are some options to fuse data acquired with separate controllers?
I'm developing my own IMU for a quadrotor.
My inputs are an accelerometer, gyro, magnetometer, and barometer all via I2C and my GPS module via serial. The I2C bus updates & transfers mu... |
H: Use 555 Timer Voltage Doubler to Increase Range of Transmission
I have seen a number of 555 timer voltage doubler circuits. I am building a fm radio transmitter like this one: I understand that the higher voltage the farther the transmission range. Would this doubler suit my purpose. Also would it drain the batter... |
H: Different roles of a resistor
I graduated in Physics, then fell in love with electronics, so, in the past few months I have been trying to make heads and tails from it on my own.
Today, as I was reading about amplifiers I got stuck with a resistor in the schematics therein.
Here goes it:
As you can see, it's a s... |
H: A basic question about this nodal analysis
I have this circuit which I have to solve for Io using nodal analysis. Everything seems easy but I am confused about the nodal equation for V2 given below in the solution. They seemed to ignore the part of the node that goes from V2 to ground, through the 2 1-ohm resistors... |
H: designing a sequential circuit by having it's value table?
when learning about combinational circuits we could draw the truth table and construct a circuit by the help of min/MAX terms . and we could further simplify it with Karnaugh maps .
BUT how we do this in a combinational circuit .
lets say i have a table l... |
H: Is the design decision for different frequencies in PAL and NTSC related to the AC mains power frequency?
In discussion a friend mentioned:
In the original implementation of PAL and NTSC they used the AC current as a means providing the frequency for the TV. As the different mains had different frequencies, they d... |
H: Regulator circuit design
I need to design a regulator for my thesis, but I really need help, Please!
The topic:
- A temperature regulator for a small fridge
Some details:
- the regulator has to control a peltier element which will cool the air in the fridge
- the peltier element functions with 12 V and 5 A
- fi... |
H: Virtually grounded negative input op amp exists but no virtually grounded positive input. why?
If the positive input of an operational amplifier is grounded, the negative input is said to be virtually grounded and it has therefore zero potential.
But the contrary is not true. A grounded negative input doesn't make ... |
H: Grounding a wire using a chunk of metal?
So I've made a complex LED grid and it works but has ghosting in some of the rows.
I've given up trying to work out the reason why, but have noticed that when I touch the SCLK wire, or connect the SCLK wire of the TLC5940 LED driver chip to a pair of scissors, or any big ch... |
H: L293ne wireing help
First real project in many years so please accept my apologies of this is a silly question.
I want to use the L293 to drive a motor (or 2). Using a raspberry pi which I have done using the add on Gert board for the raspberry pi and the single h bridge it supports.
Now to start with I have
2 X ... |
H: How exactly does a comparator work?
How exactly does a comparator work?
Comparators have many uses and its concept is not too hard to grasp. What I don't understand however is how exactly it compares two voltages.
How does it know that a certain voltage A is greater than a voltage B? And why does that trigger the c... |
H: Viability of Voltage Controlled Amplifier circuit
As part of the synthesizer project I have been working to design a simple voltage controlled amplifier. Due to the complexity of other parts of the circuit and the amount of time I've spent on this project overall I am seriously considering opting for a variable amp... |
H: Reverse polarity protection idea
I'm thinking about making a reverse polarity protection for a project. This is for a small line follower robot and I'm still deciding if I need a reverse polarity protection at all.
It will be powered by a 2S LiPoly battery and I could probably rely just on the connectors for not re... |
H: Terminal voltage of DC battery
It is said that measuring the terminal voltage of DC battery directly with a voltmeter, it can give misleading values and it is always advisable to take such readings while the battery is connected in a circuit with a certain resistance. Can anyone explain the reason behind this? And ... |
H: Additional TX and RX pins for FT232RL Microcontroller Interface
I'm designing a board that needs to be programmable via USB and external TX/RX pins. I decided to use FT232RL ( http://www.sparkfun.com/datasheets/DevTools/Arduino/FTDI%20Basic-v21-5V.pdf ) for the USB interfacing. For the external RX-TX pins, do I nee... |
H: How to regulate voltage into two variable outputs?
I'm thinking of building a control voltage generator for a synthesizer. Basically I want to control two pitch control voltages with variable resistors, something like this:
R1 needs to control only the output of CV1, and R2 only the output voltage of CV2. But wit... |
H: Can you identify this Bose car amp burned part?
Many more pictures here
The radio and amp stopped working after a battery jumpstart. I fixed the radio by simply changing a fuse but the amp has a burned part. I tried contacting Bose to no avail. I could buy a full new amp but it feels like it would be easy to fix i... |
H: Replacing normal fuse with self resetting fuse
I have a multimeter with a normal fuse that I have recently broken and I would like to replace it using a self resetting fuse with the same specifications (250mA / 250V) by soldering it in place. Would there be any draw backs?
AI: The maximum interrupting current and m... |
H: Components with multiple possible values - how to designate on schematic?
Quite often it happens to me that values of resistors or capacitors don't play such a significant role. This is mainly the case with decoupling capacitors and e.g. LED series resistors. Often in decoupling caps their ESR and other characteris... |
H: What stepper motor is in a CDROM drive?
There are countless projects online that start with "harvest the stepper motor out of an old CDROM drive." Many of these projects look super fun, but I don't have a pile of old CDROM drives around gathering dust.
What are the stats on these ubiquitous CDROM steppers, so I can... |
H: LiPo charger MCP73831 does not light an LED with it's STAT pin when done charging
I'm trying to charge a LiPo with MCP73831 with 2 LEDs for status. I have an amber LED D1 which is on when VUSB is getting power from the USB connector, which means that it's charging. And a green LED D2 that should also light up when ... |
H: What does Adafruit motorshield max amperage mean?
On the Adafruit motorshield it says "1.2A per motor (3A max)." What exactly is this telling me, that the motors are drawing 1.2 amps from the battery?
AI: It's telling you that if you try and use motors that draw more than 1.2A each, or more than a total of 3A betwe... |
H: 3.7V to 9V DC to DC boost step-up converter design help!
I need serious help choosing an IC for my project. I need a step-up boost converter to power my device from a 1000mAh or 2000mAh lithium ion battery. So far I have measured that my device only draws around 25mA when I wired in an ammeter. From looking at the ... |
H: Confusion over a simple 4060 LED blinker
I'm trying to build a simple LED blinker using a 4060BP binary counter, as per the following:
(source: bhs4.com)
and
(Originals here and here). When I have built either circuit, the LED (I'm just using one for now) is permanently on. Looking at the circuits this seems log... |
H: Measuring a voltage that is higher than your reference voltage
Question: How to measure an input power rail?
Let's say I want to build a circuit that switches in a load that draws 1A from a 5V power rail (that is the supply for the device) and then measures that rail to see if it droops and if so by how much. This ... |
H: Two opposing voltage source, of different current capacities?
If two voltage source of the same value(20V) are wired in series and they both have different current capacities, could there be any current flow assuming the resistance(internal & circuit) are equal? I assume the voltages being the same and in series to... |
H: Use reference voltage as power suppy
I am using MCP3202 which does not have Vref as independent input. The datasheet states that the current consumption is:
550 μA max. active current at 5V
Can I use a voltage reference (Series) like LT1460 to power it?
LT1460 can provide upto 20mA as stated in the datasheet.
The... |
H: Solder mask custom shape in altium
I want to have a region in my PCB without solder mask while the other regions should have solder mask. I am not sure how do I do it in Altium? To be precise I want say a custom shape solder mask free region in my PCB.
This i can use for tinning as I want more current conductivity.... |
H: Why are corresponding USB datalines connected to each other in this USB hub?
Background: this is (I think) effectively a USB hub, with built in ethernet. This is the circuit as it is being used in the Raspberry Pi B rev. 2
The USB+ from the upstream port (0) is connected to the USB+ on only one of the two downstrea... |
H: Return path on a PCB
I've spent the weekend absorbing video lectures from Eric Bogatin and reading his book "Signal and Power Integrity - Simplified"
He states that the the return path for the PCB may be any DC plane which could be a VCC rail underneath the signal path.
Consider the following simple circuit
simula... |
H: Single input instrumentation amplifier
I have an instrumentation amplifier, INA 126. I am using it to amplify the physiological signals from the eye movement. The circuit I have constructed has 2 stages: 1st stage has INA 126 with a gain of 1000 and the 2nd stage has another INA 126 also with a gain of 1000.
My qu... |
H: Finding Vc in this simple circuit
simulate this circuit – Schematic created using CircuitLab
Forgive me if it's a basic question, but I am stuck with this. Is this the correct way to do it:
Do voltage division between R1 and R3 to find the voltage on R3. Then do voltage division again between R3 and Vc to find Vc... |
H: NPN BJT used for DC Switching Load
I am trying to learn some things for a class. This is not homework, just studying for an exma. It has to with calculating values when using a NPN BJT. I have five (only three because other 2 were not relevant) questions attached, but I really just need help with questions 1 and 2.... |
H: How do you measure the actual package temperature of PCB components?
We have an IR thermometer at work, but sometimes I feel like the results aren't completely accurate due to the beam width (especially on small components) or material emissivity.
Another way I've tried is to use a thermocouple temperature sensor f... |
H: Meaning of AC15, DC1, AC1, and DC13 in relay durability curves
In the datasheet of the relay OMRO G7SA from the durability curve they specify the number of operations as a function of the contact current.
Each curve is for a specific current and voltage. The curves are labeled DC13, AC15, DC1 and AC1. Can anyone te... |
H: SIM800L power interface
I would like to use SIM800L for M2M. I have power of 5V 2A for powering uC board and would like to add gsm module. It seems that SIM800L has rather strange voltage input rating: 3.4V - 4.4V.
What would be proper way to power it up with this configuration?
One proposal was to use zener diode ... |
H: Difference Between LM386 and LM741
What is the Difference Between the Normal Opamp LM741 and the Audio Power amplifier LM386..
I mean in both the circuit we use the concept of voltage compensation, then how come LM386 is called power amplification also,
What is the difference between Operational Amplifier and Power... |
H: Makeshift way to drain a battery?
I have a 3.8V mobile-phone battery that I need to discharge.
However I don't have any electrical components (say led) with me.
What is a crude way to do this using household items?
AI: The "lead" of a modern pencil is made of Graphite. Graphite is a form of Carbon. Carbon is what ... |
H: Finding the transfer function of this RC circuit
I have the following circuit and I need to find the transfer function:
simulate this circuit – Schematic created using CircuitLab
Considering the position of \$V_{\text{out}}\$, it looks like I can combine the \$R\$ and \$C\$ in parallel both above and below \$V_{\t... |
H: I2C hanging after 2 minutes
Background Information
I am designing a small PCB for 4* I2C devices, the baud rate of the I2C is not a major issue so 100kHz was the target. The I2C devices are a RTC, LM75, 24AA04 and a MSP23017 to drive an LCD, the board is made using a LPKF milling machine. Before fully populating... |
H: Why does Nyquist plot only need loop gain but not the entire closed loop transfer function?
I was trying to compare a Bode plot and a Nyquist plot of the same system and realized that I was probably comparing apples to oranges
Bode plot is plotting the entire closed loop transfer function, whereas the Nyquist plot ... |
H: no-load DC output voltage of DC wall-wart circuit
I have this question and I believe the answer is 12.73 from the equation
V(N) = V(Rated) * sqrt(2).
Is this the correct formula and can someone show me how we arrive at it if it is. I am unsure about the derivation so I am unsure about whether the a change in the ... |
H: Interfacing a GPRS chip (WISMO218) with an RF antenna. Calculating line width for the right impedance
I want to interface the WISMO218 GPRS chip with an antenna. The antenna lines on the PCB board have to be very specific, otherwise the system won't work. I have uploaded the part of the datasheet that refers to the... |
H: How to design a PID controller with no additional i) gain margin, ii) phase margin?
Given a system G(s), how do I design a controller C(s) such that no additional phase or gain margin is incurred? I would like to do this analytically
Surely I could go through the step of drawing a Nyquist plot of the CP(s) system a... |
H: What is the difference between a solid state relay and a transistor?
Along with the difference between a solid state relay and a transistor, I'm also interested to know if there are transistors that act a lot like the typical relay modules you can find on ebay (where you only need a 5V signal from the microcontroll... |
H: Resistor for maximum water electrolysis
I've partaken in an experiment where I am looking to create the most efficient way to conduct water electrolysis.
My only need is that I don't trip a breaker. I will be running at 120vac, and likely a 15 amp breaker.
I've been looking at resistors, and I understand the ohms... |
H: Help me understand this load detecting circuit
I'm looking at this circuit:
Which has come from here
The claim is made that "it detects a voltage drop across a large bridge rectifier that acts as a high power shunt", which is referring to the transformer wired across D1.
However, that transformer appears to be wir... |
H: finding I(current)
I am learning about step response in RC and RL circuits and one of the problems i managed to redraw as the image above; however, when I am solving for i the answer is -5mA. I am just confused on why it is negative as soon in the image, I understand that I just use ohms law here to attain i. In o... |
H: Why use a N channel MOSFET as high side H bridge switches?
I've seen N channel MOSFETs as high side switches of H bridges quite often, which requires a charge pump to drive. Wouldn't a P channel MOSFET be easier, simply isolating the microcontroller command from the gate source voltage? Why use the N channels inste... |
H: VHDL difference between component and subprogram
I've read different article (and book chapter too) about "component" and "subprogram".
What i don't understand is what is the difference between the two...
I mean, i know that the component make easier the "hierarchical design" grouping "hardware pieces" somehow, whi... |
H: Trace vs Plane on Multi-Layer Board
Designing a 4-layer board (signal+pwr, gnd, signal+pwr, gnd), and I have some newbie doubts about the best option to connect different connector's pin or IC's pad to power lines, or sometimes to different signals.
Board has different parts: Power, MCU & RF.
The main issues I have... |
H: Why Op Amp circuit not behaving as desired
I want to convert PWM output of microcontroller to 4-20mA. I use below circuit for this
work :
But voltage on pin + and - Are not equal in this circuit!!! for example when pin + is 1.2 volt with voltmeter ,pin - is 2.04 volt . while They should be equal http://en.wikipe... |
H: Software interrupt vs function
After about 3 years of working with MCUs still I don't know what's the use of Software interrupts? I have done several jobs with STM32 and I have never used the software interrupts. Indeed this is a big question to me:
Why when we can use a simple function to do a task, should we use ... |
H: Mains Voltage on Strip Board
I need to prototype something quickly as a proof of concept. Is it safe to use mains (UK 230V) on stripboard? It will be going to a transformer so I can control some appliance. Or should I design a custom PCB to do this?
AI: "Is it safe?" cannot be answered as you haven't provided enoug... |
H: Semaphore using one microcontroller pin
I'm trying to make a semaphore using to LEDs green and red, controlled by one arduino pin. Idea is when pin is low red LED is on and green LED is off, when pin is up green LED is on and red LED is off.
So I've made the circuit using two transistors and in simulation software ... |
H: Serial port communication
I have transmitted the data from a PC to other devices using a serial port cable. In that case I was using windows 7 32 bit os. But when I tried it with 64 bit os I am not able to transmit it. Is there a way to transmit the data from a PC with windows 7, 64bit is?
AI: A PC Serial port is a... |
H: 555 Timer Zapper
I want to make a simple bug zapper. I was planning to make a cockroach zapper but I want it to be a small DC application and dont have any transformers on hand so I may have to settle for a zapper the zapps smaller bugs. So I found these circuits at this site.
Disregarding the names do you think ... |
H: Code Converter Circuit
Make a BCD to Excess-3 Code Converter by using a binary to decimal encoder and 4 OR gates.
I know how to make a binary to decimal encoder, but how do I proceed from there?
AI: Write down your 10 inputs, D0 to D9 and the Excess03 code (4 outputs).
Table will have 10 lines. You will have 4 inp... |
H: closing a circuit programatically if ground can't be interrupted
I need to be able to "push" a button on a control panel using python and an arduino board.
My problem here is that the button in question, when depressed, sends 16 vdc to an outgoing wire that disappears into the bowels of a very large machine. Isola... |
H: Coplanar waveguide vs open space?
I'm routing a U.FL connector to a cellular module (Telit GE864).
According to this calculator a 1mm track with 0.16mm gaps should provide a 52Ω impedance path to an U.FL antenna connector.
A Sparkfun breakout board for a similar module uses an open space (~1 cm high) with a far wid... |
H: "zero voltage drop diode"...Really?
In my research for this question, I found this by a new user that hasn't been seen before or since. His low investment here and the "say goodbye to traditional bad stuff" language makes his answer a bit dubious, but just in case he's onto something, I thought I'd fish for some c... |
H: What is the name of contractors designing high power supplies with relay logic?
I have been designing a 3 phase power supply with distribution strip and redundant contactors with failure detection (I posted a question not long ago related to that, it's based on relay logic), and since we do not have related experie... |
H: Is it permissible to use fractional aspect ratio W/L for MOSFETs?
I am designing a 2-stage op-amp (Miller compensated). For compensation, I am using a nulling resistance R in series with the compensation capacitance C, with the resistance implemented using a transistor biased in the triode region.
The circuit is s... |
H: Arduino resetting/hanging due to sparks in ac line
This is the PCB design of the project I have been working on recently (my first pcb design).
The idea is to control ac appliances (fans, bulbs etc) without relays. I am using triacs which are better than relays for such applications. I am using opto-isolators for... |
H: Homemade dynamo and alternator
I'm a curious person that knows only basic physics, and I want to craft a homemade power generator (eolic, magnetic or hydroelectric, the origin of the energy doesn't matter yet).
I would like to find formulas to determine the possible output in volts and watts. I think these will tel... |
H: Can a battery powered circuit experience input voltage overshoot on turn-on?
I'm trying to track down why my SMPS stopped working. One thing that caught my attention is this paragraph in the datasheet for the regulator:
I'm using a 2700mAh 3S LiPo (rated at 35C, 70C peak) connected through about 18" of speaker wir... |
H: Logical Design Operation, A Simple Questions?
I'm so sorry if I ask my first question that so simple. My filed is Math and Computer science. I self-study Digital Design.
My challenge is how we can find the operation of the two following Diagram
?
AI: It's been a long time since I've done this the long way.
The... |
H: How does a transformer transmit power from the primary to the secondary?
I'm trying to get my head wrapped around transformer operation and in the process regretting the times I snoozed in my Electromagnetics class as a EE student back when I was a lad :)
I'm looking for an intuitive understanding, but not just an ... |
H: "LB" component reference designator
I'm doing a bit of reverse engineering on my Das Keyboard Model S Ultimate. I'm beginning to develop a pretty good understanding of the circuitry, but I am confused about one type of component on the board.
There are 4-5 components on this board with the reference designator of L... |
H: What's the relationship between ESC pwm input and output?
I'm using ESC(Electronic speed controller) to control outrunner brushless dc motor.
As you know ESC detects ppm signal between 1ms and 2 ms approximately. So my ESC detects signal between 4% and 9% duty cycle at 50 Hz as an input.
However, it is unknown what... |
H: Should PCBs be rinsed after being cleaned with IPA?
A lot of people recommend using 99% IPA to clean flux (and other stuff) off PCBs. I haven't been rinsing off boards after cleaning with IPA as to my knowledge it's not corrosive, but I'd like to hear from someone more experienced on the matter.
Should I be rinsing... |
H: Using transistors to minimize the number of Arduino pins used for this stepper motor driver
Alright, I know very little about what I am currently asking about, but here is the gist of it:
I want to build a cnc machine out of some old floppy drives. I purchased a couple L293D dual H-bridge ICs to drive the stepper m... |
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