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H: AVR diagram of functions calling, ISR and main loop share the same resource
I made a simple diagram of functions calls to illustrate the potential problem which bothering me a little. As you can see, my task_list (which is simple linked list) is modified either in ISR and program main loop.
Can this solution cau... |
H: LM339 Lipo Battery Voltage Tester Circuit - How does it work?
After reviewing the eevblog video on OpAmps and various other videos on the LM339, as well as copying a circuit which works, I am still genuinely confused on the math / logic behind this, which makes it hard to move on to more complicated and customized ... |
H: Determine the resistor required for a circuit
If I want to supply power to a device that is rated for about 2V using a DC source of 12V. How can I find the resistor o should use.
AI: It depends on the current required for your device.
If the current required is next to nothing, then a simple voltage divider will do... |
H: Confusion about voltage at negative terminal of capacitor
I have some confusion about the negative terminal of a capacitor. Consider the following
Now, my understanding was that postive charges accumulate at the positive ("top") plate of the capacitor, setting up an electric field within the capacitor which causes... |
H: Directly wire inverter to switches/lights/etc
I have a 12V deep cycle marine battery that is charged by a 20W solar panel. This works well. However I would like to use the battery to run two 120V 170mA 15W LED lights in a shed. So as I understand it, that means I need to connect an inverter to the battery to change... |
H: Power-on delay with 555 Timer
I am trying to create a power-on delay with a 555 timer IC. I have never used one of these before and I am finding it a bit tricky to make applications with it - a lot going on.
I found this circuit online
I also saw this from GreatScott showing the internals
My question is in relati... |
H: How to create large inductors (1H) for audio use?
I am building a tube amplifier, and have decided to add a 5ch EQ to it. Historically, the ones used in guitar amplifiers were all passive RLC filter style systems, with large inductances of 0.5 - 2H for the 80Hz channel.
I know now days it would be smaller to use an... |
H: Help me understand my campervan split charge relay
I am new to the world of electronics, but keen to learn. The below all relates to the 12 V circuit of my van.
I have picked up a campervan which has a second "leisure" battery which powers items in the rear, such as LED lights etc. These lights run off a caravan-st... |
H: How to get the IC numbers of the logisim items
Logisim makes it very easy for user to intuitively manipulate and edit the components already provided to achieve the circuit he wants. But there is no information about the actual IC numbers of those components which is present in Proteus. I could just do a google sea... |
H: instant current in very long transmission line
In reading the definition of impedance matched wiring a question popped into my head that I can’t seem to find the answer to. Assuming a 50 ohm impedance line that is infinity long, then in theory if I attached a voltmeter I am able to see 50 ohm resistance. However wh... |
H: LtSpice antisymmetric sine pulse
I am trying to create a pulse voltage source in ltspice. The pulse should look like a half cycle of a sine wave however the rise and fall times should be different. I can create such pulse with the PULSE function of ltspice and can create a half cycle sine wave but I don't know how ... |
H: PCB etching not working: everything etched
I tried to etch a PCB with the photoresist method, using sodium hydroxid as developer and ferric chlorid as etcher. I think the problem is in the development phase. Although reading a lot about etching, I seem to make a big mistake.
Here is what I did:
I printed my circui... |
H: What is the advantage of putting capacitors in parallel with glass fuse tube
I have seen a board and I wonder to know what would be the advantage of having capacitor in parallel with fuse.
AI: The capacitor is placed for protecting fuse in switch on/off system.
Most loads are inductive such as motors and light bulb... |
H: Can an Integrated Circuit ROM ever be secured
This presentation which includes embedding public asymmetric crypto assets in a micro-controller on chip ROM suggests that there are, but I am sceptical.
Is it the case that there is nothing that can ever be done to hide the physical chip design from an examiner
AI: You... |
H: Some questions about a series pass transistor & op amp voltage regulator
I have the following voltage regulator using a series pass transistor and an op amp providing the base voltage:
I have three questions:
How do you calculate the output voltage for such a regulator? I can see that it is equal to 9V but I'm wo... |
H: Parallel RC as a filter?
I was looking at an amplifier schematic and saw a curious portion that I realized I wasn't sure what its purpose was.
simulate this circuit – Schematic created using CircuitLab
At first glance I thought I saw a low pass filter, but then I said wait no, those are in parallel. What's that c... |
H: How to obtain SNR when we have the samples of a non-DC noisy signal in practice?
This may sound a naive question but I couldn't find an example. Let me begin with what I know about SNR and where I am confused.
Lets say I have a DC like signal with some random noise on it and I have the samples. I can then by using ... |
H: Operating ultrasonic transducers
I have constructed my circuit as shown in the picture. I am using raspberry pi to generate PWM to the transistor base and an MCP3008 to convert the anolog signals from the receiver. However, both the transmitter and receiver are not working at as intended. When probed with oscillos... |
H: Is there a simple way to discharge a bipolar capacitor using a 5V signal and a MOSFET/BJT?
I am using an op amp configured as an integrator, as shown in the schematic below. There is an input signal which can go both positive and negative [+1V ... -1V], and then depending on this input signal polarity the output of... |
H: How to build a programmable LED strip?
I'm trying to build a home-made LED strip (non-RGB). It will be using single color SMD chips in array. The thought I have right now is to have 3 rows, each with about 15 or 25 same single color LEDs, will be sitting on custom design PCB board.
The goal is to have it programmab... |
H: Arrangement of discharge resistors for capacitors in series
These 2 circuits consist of voltage source, 2 capacitors in series and their discharging resistors.
Capacitors C1 and C2 are put in series because voltage V1 is higher than rated voltage of each capacitor. Nominal values of capacitors and resistors are the... |
H: How to set forward voltage for a diode model in NGSpice?
I am trying to understand the documentation for the diode model, but I could not find how to set the forward voltage value.
Can someone help me simulate silicon diode that has a forward voltage of approximately 0.7 volts?
AI: You do not simply "set" the forwa... |
H: How do you make an ideal circuit?
I was reviewing for our class and I can't seem to understand how the book comes up with these answers.
AI: I am not going to ans but give you hints to solve.
Observe the direction of 8A current source and ib.
Observe Vg source and 8A source, how they are connected in and its pola... |
H: Why are registers being turned on to 1 before reset/on button is hit on FPGA?
I am writing a really simple program on Verilog for my FPGA to have an LED blink once a button is pushed. Here is the code I have written:
module hello_world(
input ron, //reset button (ron = reset/on)
input clk, ... |
H: Why is voltage across LED filament bulb slowly decreasing?
I'm trying to power this LED filament bulb with a 12V - 2A DC wall adapter.
LED specs:
rated at 4W
12 to 24V input
I'm pretty new to this, but if I get it right:
Calculus
the LED bulb will draw E/V = 4/12 = 0.33A if power source is at 12V.
by measuring ... |
H: Voltage Threshold Gate Circuit from 0-5V Input
Background:
I have a circuit in which when Vin is applied, the super capacitors have to be charged before anything else in the circuit can be utilized (otherwise I will undervolt the devices I am trying to power and they will not turn on). Therefore, I am trying to fi... |
H: How do I know to choose a first order filter vs a second order filter?
I have a DC signal coming off of a battery. The Arduino is reading the voltage. The issue is that the voltage signal contains a lot of noise (120hz frequency). I am planning on building a first order low pass filter but how can I know if first o... |
H: Can I strobe a power led with an audio power amplifier?
I'm trying to make a fast LED strobe for visual periodic measurements of mechanisms, rotating objects to be specific. I "designed" an opto-coupler/MOSFET circuit and a transistor/MOSFET circuit. I plan to have an Arduino as the precision strobe signal source s... |
H: How do I determine the output voltage in this diode circuit schematic?
What is the sketch of the output voltage (Vo) when the input voltage (Vi) is 5sin(t) V? Assume these are ideal diodes. I am confused because when Vi is 0V, the only 1V is dropped across the resistor due to the current source and there is 14V lef... |
H: Why arc only happens when circuit on load?
I'm preparing research about high voltage electric distribution for my university but I don't understand why the arc only happen when current is flowing.
I made my internship in an electric distribution company and they told me you can't use disconnectors when a circuit is... |
H: Voltage drop after optocoupler
I don't know what's wrong... I have an ATTiny13 which gives a dummy impulse turning a fan on and off every 2 seconds; so the plan.
I attach two power sources (for dummy purpose) before and after the optocoupler (5V on the top right; and DV on the center bottom). In the experiment both... |
H: Step-up converter current limit 2A
In the specification for the step-up booster is max. output current limit 2 A (or any other value based on the specific booster). Does this limit apply for the whole range of supported voltage or for the lowest voltage?
AI: Read the specifications in the datasheet. If the booster ... |
H: Finding out the accuracy of the current probe's measurement
As part of power supply testing we are measuring the current profiles of various regulators.
Startup profiles includes current bursts with different current amplitudes and widths.
i want to understand the accuracy of the current probe*(MINIMUM CURRENT WHIC... |
H: How should a watchdog timer be used?
I've seen and written programs in which the internal watchdog just resets in a super loop and trigers only when something goes wrong and forces the whole system to crash.
I've also seen it can be used as a "system reset" when the program intentionally goes into an infinite loop ... |
H: Confusion regarding a 12V DC motor's RPM
I have a 550 DC motor of 12V, 45W and 10K RPM installed on a wheel, which is not causing the wheel to turn fast enough when the motor is connected to a 12V battery.
I replaced the motor with an older DC motor which I had, having the same specs of the replacement, however wit... |
H: How to program STM32_F4VE with ST-LINK/V2/01-0
I am using keil uvision 5. I haveSTM32_F4VE development board and ST-LINK/V2/01-0.
How to program this board with ST-Link v2? If you can suggest some website link also it would be helpful.
AI: * Install STM32 STLink Utility.
* Install STSW-LINK009 driver.
* Connect ST-... |
H: Why aren’t the magnitude comparators cascaded the “more efficient” way?
In Practical Electronics for Inventors, Paul shows the following cascading of two \$ 74HC85 \$’s to build an 8-bit magnitude comparator.
Question: Why doesn’t he cascade them in the apparently more efficient way where the higher order bits are ... |
H: How does the second order time constant affect circuit behavior?
I learned that the transfer function of a second order circuit can be expressed in the following standard way:
$$
\frac{K}{\tau_s^2 s^2 + 2 \zeta \tau_s s + 1}
$$
Where:
\$K\$ is the gain
\$\zeta\$ is the damping factor
\$\tau_s\$ is the second orde... |
H: Mitigation of dead zones when applying circular polarized antenna
I would like to know if I used a circular polarized (RHCP) antenna inside a metal container as show in the configuration below will it reduce the dead zones, as compared to a linear polarized antenna?
From the research I have done when RHCP EM wave r... |
H: Is it possible to manufactrure a stencil for this paste-mask using the usual stencil making methods?
I have this footprint from the KI-CAD footprint library (LFCSP-32-1EP_5x5mm_P0.5mm_EP3.1x3.1mm_ThermalVias).
The paste-mask shows several circular paste areas under the thermal pad. The separation between the paste... |
H: Help with I2C Communication
I'm trying to learn how to program a battery charging IC (BQ24193) via the I2C communication protocol. My goal is to write the correct values to it in order to gain the proper charging input and output current (I will be using an arduino to program this if that matters).
When going thro... |
H: Components for new designs
I'm replicating an open source pcba in order to learn how to build more complex PCBs and there is a part that is not recommended for new designs:
https://www.mouser.com/ProductDetail/TDK/VLS252012ET-4R7M?qs=uxmvvYJjMIsaASiY9mND9w%3D%3D
What would be the best part to replace it with?
AI: I... |
H: What is automatic global reset on FPGA?
I recently asked a question that ended up involving answers about an automatic global reset capability that FPGAs have, and though the question got solved, I'm still quite unclear about this, and would like more information. I tried to scour the web, but wasn't able to find s... |
H: Voltage Divider Configuration of Transistor
I have a voltage divider configuration for biasing my transistor. The gain of transistor is lets say 150 which is typical value for BC547.
What I want is limit the current flowing through the base to be 10 micro amps.
Doing the Thevenin's analysis gives me the Thevenin Vo... |
H: Identify 19-pin connector that looks like USB micro
We use a satellite modem that sports a 19-pin connector. There is a handy connector on the board to let us communicate with it, but the supplier doesn't know what brand/model the connector is, and the manufacturer is incommunicado. We're reduced to using a proprie... |
H: Safety precautions when developing and testing mains voltage devices
Specifically, I am planning to design and build an energy meter to measure power drawn from mains - 120V 60Hz.
What are the risks associated with developing and testing this device and how to minimize/eliminate them?
AI: This is such an important ... |
H: Passing <5V through bus of tri-state transceiver
I am following a schematic which implements a basic 8-bit register. The schematic is pictured below:
According to the datasheet of the 74LS173 chip, The high-level output voltage is 2.4V with testing conditions assuming the minimum input voltage (although my case Vc... |
H: Can an electrified wire ever be safe against bare skin?
This could sound ridiculous to someone with an ounce of experience, but I'm just getting started, so here we go ;) Full question is 3 parts...
First, what is the lowest amperage needed to light an LED? I think there are blue LEDs that can light up at 5 mA. 10 ... |
H: How to understand these 8086 bus cycle timing diagrams
Please see the two diagrams below.
In the first diagram, each state (T1, T2, ...) seems to begin with the clock low.
In the second diagram - with the clock high.
If we look at the DR/R' signal - in the first diagram it appears to be set low half a cycle before ... |
H: Voltage dip at source side during heavy loads due to Internal Resistance
In any application, during initial start-up/load step, there is an high current requirement. Due to this high current requirement, there is a dip in that connected voltage rail.
I researched on why there is a dip in the voltage rail during st... |
H: STM32F103rb datasheet mentions 4gb address space, while only 128kb flash and 20kb RAM?
I am trying to advance my way into the STM32F103RB, and I don't understand the address space mapping defined in chapter 3.2 in the the STM32F103RB datasheet.
It states:
Program memory, data memory, registers and I/O ports are or... |
H: Voltage doubler and power
Lets consider for instance this voltage doubler:
It was told that a practical limit of this circuit is the fact that we cannot absorb too much current from it. But I wanted to verify (if it is true) this by analyzing the circuit. Intuitively I may think that, since the maximum power which... |
H: LM2596T, Inductor selection
I'm trying to build a simple low voltage 0-12 adjustable PSU and the simplest way i could think of was using a LM2596T ADJ.
In page 16 of the Datasheet there's a inductor selection selection guide, in my case figure 7:
Can someone please explain this graph for me? how can i choose the ... |
H: Surge protector outlet with altered grounding potential
I realized that I have a voltage difference of 5 to 80 V AC (orange in Fig. 1) between the protective conductors (grounding cables, "PE-Leiter", yellow-green contacts in drawing) before vs. after a surge protection device (Fig. 1: red box; photo in Fig. 2). Al... |
H: measuring ac voltage drop across a resistor with a solenoid in series with it
I wanted to measure the phase difference between the current (magnetic field due to the solenoid) and the system response. I am doing this by measuring the voltage drop across the resistor in series with the solenoid and using this as the... |
H: Test grounding of wall sockets
I just had (and solved thanks SE) a problem with a wall socket where the ground contacts were malfunctional. Much of the electrical safety relies on proper grounding. As far as I can read, details for state-of-the-art measurement of grounding is a science for itself, but the described... |
H: Place(s) for ground (PE) and neutral (N) connections in TN-C-S
Where is/are the correct place(s) where PE (ground) and N (neutral) should be connected in a 230 V TN-C-S network? One or multiple times?
In the fusebox of my rental apartment (several apartments per house), the thick "inward" cable contains yellow-gre... |
H: Accessing the STM32L412KB Serial Wire Debugger (SWD) Connections (Novice User)
I am attempting to program an STM32L412KB device using ST-Link/V2-1, a Raspberry Pi 3B+ and OpenOCD software.
To do this however, I require access to the SWDIO connection and the SWDCLK connection of the ST-Link on the STM32. From lookin... |
H: Half H-Bridge Driver
I'm working on a project to control power sideview mirrors in a car, with features like TildDown, that tilts some of the mirror down helping to park. The circuit is pretty simple, but I'm having some difficulty to turn the power mirror motors with my microcontroller.
It needs to be a Half H-Br... |
H: Mount position inertial measurement units (IMU)
currently I am reading about IMUs and got confused about the mounting position of the IMUs.
In this paper (https://pdfs.semanticscholar.org/c2b6/9d5f4cf0fbbbad97d1fc10b3757f9c41bb8f.pdf) , the author mounts the IMU on the center of joint rotation.
But in some other ... |
H: Why would an AC motor heavily shake when driven with certain frequencies?
I have an AC motor from an old TCL 160 Boxford NC Lathe, it has three wires named U V and W.
I thought that incorparating the original driver to a modern control interface card would be difficult or unreliable, so I got the motor out and wire... |
H: EAGLE - StopMask DRC Error
I cant understand what this DRC error means.
Especially I do not understand this box. Does it mean that the Soldermask will cover part of the pad? How to correct it?
AI: It's due to the fact that your reference designator font is "proportional", not "vector".
Proportional fonts in eagle ... |
H: Can I avoid blind vias in this PCI-E gold finger fanout?
I'm planning a PCB project with PCI-E connector. After looking at some docs about PCI-E, I found one problem regarding the fanout the PCI-E gold fingers, the X16 pinout defines as below (part of whole 164 pins):
You see, the opposite side of two GND pins are... |
H: Capacitors with same voltage, same capacitance, same temp, different diameter?
I recently had an old LCD monitor power supply go bad and figured I would try replacing the caps, all four of these were bulged and or leaking. They are all rated to 105 degrees C, all 1000uF and 25V yet two of them are much higher diame... |
H: Placement of the microcontroller on the back of the board with LEDs
I am designing a board with 9 SK6812 LEDs.
On the back of the board I want to place the Atmega328P microcontroller.
I have doubts whether the heating of the LED can affect the operation of the microcontroller?
Board Thickness: 1.6mm
Two layers
AI: ... |
H: KiCad: "No footprint for automated placement"
I just finished my first PCB with KiCad. Now, I need to produce it and I need the Pick and Place file. When I try to generate footprint position files the software produce the message "No footprint for automated placement". I'm using the version 5.1.4-e60b266 for ubuntu... |
H: Identification of ribbon cable connector
I need to identify this 15 wire ribbon cable connector, does anyone happen to recognise this? Assuming it’s not easy to find can anyone suggest where I can buy a replacement?
AI: I think it is an IDC to DIP (See below)
(Took me a few minutes to find on the digikey website us... |
H: What is the name/purpose of this component?
I was wondering what is the role/purpose of the electric component in the red square.
This is the schematic of a 230V single phase induction motor.
What is also not clear to me are the connections on the right side.
The first two wires are neutral (blue) and live (brown)... |
H: Confusion regarding Common-Emitter configuration of a BJT
This is a picture of a Common-Emitter Configuration of an n-p-n BJT, taken from a book :-
For the BJT to be in active mode, the Base-Emitter junction should be forward biased, and the Collector-Base junction should be reverse biased.
Here, I am having diffi... |
H: wien bridge oscillator transfer function
I am trying to calculate the transfer function of a wien bridge oscillator but there is something wrong in my calculations.
In the picture below there are my results from this calcultation. I am using signal flow graphs
results from maxim
AI: To determine the transfer functi... |
H: What did I do wrong with this switching voltage regulator circuit (LM2574)?
I'm new to the electronics world. I've been trying to build a switching voltage regulator circuit using the LM2574N-5G (datasheet) IC. I'm trying to switch 9V (from a 9V battery) to around 5V. I've tried to implement the circuit that the da... |
H: SR Latch internal conflicts
it is known that "11" are invalid inputs for a SR Latch. But I do not understand the reason of that. I cannot see the electrical conflict in this structure:
If R = 1, its NOR gate will give 0, for any value of the other input signal.
If S = 1, its NOR gate will give 0, for any value of... |
H: How come (x*y)+(x*z')+(y*z) = (x*z')+(y*z)?
As the title says, I just can't figure this one out.
I started with the initial function: f(x,y,z) = (x'yz) + (xy'z') + (xyz') + (xyz) and I have simplified it all the way down to this:
f=(xy)+(xz')+(yz).
I found out that the solution was: f=(xz')+(yz) but I can't see h... |
H: Is the wattage important when buying a replacement solder tip?
I have a Weller SP15N (15 watt) soldering iron which needs a replacement tip. It needs 3.5mm tips.
Replacement tips on ebay often come with what looks like a wattage rating.
Why do tips come with wattage ratings, and is that rating a max. rating? In oth... |
H: Voltage of capacitors for MIC29302
I want to use MIC29302 as regulator in SIM800L circuit.
In the suggested circuit in the datasheet there is a 100 µF capacitor before the regulator and a 330 µF capacitor after the regulator, but there is no information about the voltage of these capacitors in it.
How should I cho... |
H: Is it safe to directly connect an infrared led to an Arduino?
I have a KY-005 infrared transmitter connected to my Arduino Uno. But currently I can't get it to work. On this website it says that you must connect the led directly to a digital pin on the Arduino, which I have not done (I connected it in series with a... |
H: Simple circuit with an inductor in transient state
I have a problem with this circuit. I am supposed to calculate i(t) at the moment t=(0+).
The parameters are:R=300Ωe(t)=12VL=0.1H Switch is closed at t=0
I know that current can't jump in the branch with the inductor, so
iL(0+)=iL(0)=20mA
but I'm not sure what will... |
H: Integrator with DC control gain
I am analyzing the integrator circuit and I can't get from which equation can I get the frequency where there is the intersection with x axis - 1/C*R1 ?
Thanks!
source
AI: Well, first of all we can look at the wiki-page of 'Operational amplifier applications' and look under 'Invertin... |
H: State Diagram with two inputs
For a lab exercise I have to design a 2-input sequence and I'm struggling with the state diagram, as It has 2 inputs, A,B and it says that in the start if we have same values the exit Y=1 and Y=0 when are different. When it finds 3 continuously same values of inputs the exit will rever... |
H: Connecting 3phase motor to FC
I'm connecting 3 phase motor to frequency converter and I don't understand why to use shield cables. Is using shield cables a must in every situation or only when nearby is running a Profinet or other sensitive signals?
AI: A variable frequency drive (VFD) uses PWM to simulate a sine w... |
H: Filttering noise out from high frequency 1MHz oscilator (Teslacoil driver)
I have a 74HCT14N based ''RC'' square-wave oscillator.
The produced signal then goes to PMIC gate-driver and finally to a mosfet which drives the primary coil at resonant frequency. (about 930-1000kHz)
It is a hobby project, and I'm learning... |
H: Can I use a cheap logic analyzer as a USB to UART TTL cable?
I need a USB to UART (TTL) cable for connecting to an onboard JTAG connector. Since I already own a Sigrok logic analyzer, I figure it might function soley as a USB to UART cable. Is this possible?
Here's my Logic analyzer:
https://learn.sparkfun.com/tu... |
H: Capacitors capacity in an RLC circuit that is in resonance
So if its in resonance that means XL=XC right?
anyway thats how I started
I∠=Irms∠=7.07/sqrt2 ∠30° A
ω=10^3
Z1=R+jXL=1+1∠90°=sqrt2∠45°
Z2=-jXC=1∠-90°
Ztotal=(1/Z1+1/Z2)^-1=sqrt2∠-45°
U∠=I∠*Ztotal∠
U∠=7.07∠-15° V
I2∠=U∠/Z2=7.07∠75
UL∠=U∠, I2∠=I∠
UL=I/Cjω
C... |
H: What is negative current?
I understand that voltage is relative to ground, so that can be negative.
However, I'm currently looking at current-sensors (ACS712 current sensor) and in the performance characteristics table, it specifies the Optimized Accuracy Range.
In the case of this sensor, it's being specified in ... |
H: Traco DC-DC Converter
I am using THN 15-1215N for generating 24V from 12V input. Since this module has a second output(Negative) can I connect this to the ground to obtain only a single output?
Edit:-
I am using the module for designing a board, for future purposes i have included few 0R resistor for trimming the o... |
H: NMOS bootstrapping without an IC
Like the title says, I was trying to bootstrap a high-side NMOS. After some googling I found this video https://youtu.be/zcQV_ZpK1W8 which helped me a lot except for one thing which I cannot understand.
Now, my proposed circuit is this
It is pretty much similar to his but with the ... |
H: Does input impedance of an isolation amplifier or a transformer have impact on common mode to differential mode conversion?
I have a question where I can only explain it clearly by an example. It is about conversion of common-mode interference to differential mode due to overall system imbalance.
I will use below ... |
H: "Not enough RAM " error in PIC16F877a
I have been trying to run the following code:
void reset();
int board[8][8];
int i,switcher,j,k;
void main() {
TRISB = 0X00;
TRISD = 0X00;
TRISC = 0X00;
reset();
ADCON1 = 0X06;
TRISA =0X11;
while(1)
{
for( i=0;i<16;i++)
{
... |
H: Adjustable LDO feedback resistor values
I'm designing a circuit using an LDO voltage regulator; specifically the LD39130SPUR from ST. This variant of the part allows for an adjustable output voltage via a potential divider as seen on page 8 of the datasheet. Usually, when using adjustable LDOs and other similar par... |
H: Logarithmic Multi - Stage Amplifier
let's consider this logarithmic multi - stage amplifier:
Each stage is an amplifier with this mechanism: if the input signal is small (under a certain threshold), it is amplified with high gain A; if it is large (over the previous threshold), it is amplified with unitary gain.
T... |
H: DC Power Line Communication (PLC) low pass filters
I've seen many times that a low pass filter needs to be implemented before a switching power supply in DC power line communication transceiver boards.
Why is that? I assume that the switching power supply absorbs the modulated signal, right? Would it be the same if... |
H: Switching between 2 24V 30A power sources
I am trying to make a changeover switch. The current at full load which the switch needs to handle is 30A.
I looked into automotive relays, but I believe they are not rated for continuous use.
I also found out about shotcky diodes, but I believe they are not suited for my n... |
H: Can Vds ever becomes negative in mosfet?
Due to the symmetry in mosfet, source and drain are interchangeable. So we define the source of nmos is the terminal with the lower voltage. So if we force Vds to become negative the drain and source should flip. So Vds becomes positive again.
If that is true then the follow... |
H: Fundamentals of Output Characteristics of a BJT, what is the difference between load line and output characteristics?
In any transistor, we plot the output characteristics, i.e. effect of change in Vce on Ic.
Next, we write the KVL equation on the transistor, i.e. Vcc = IcRc + Vce and plot the load line from this ... |
H: Tp4056 Module 12V input
I want to build a lithium ion battery charger with tp4056 module but most of my power supply's voltage is 12-19 V
Datasheet says input voltage is 4.5-5.5v and current 1A
Can I connect 1-3 tp4056 module in series ?
I think it won't work because voltage drop not constant ( depends on how mu... |
H: Safety: Can I harm myself using an AC, 9V 500mA power supply for experiments?
I'm about to embark on my first electronics project and would like to check off a safety question:
I want to build a bicycle hub dynamo -> USB charger based on these instructions.
It is basically a rectifier circuit to convert 6V, 3W AC p... |
H: Identifying weird component on PCB
In optical LIN converter PCB there is a weird element glued:
A plastic ring with resin/ plastic fulfillment.
Is it some sort of local coating or chip-on-board encapsulation?
There are no elements in this area on the opposite side of PCB, just 2 Vias.
AI: In the PCB industry this i... |
H: How to connect multiple sensors to single PLC input?
Hello. I have a scenario where I have multiple PNP "error signal" from several sensors (let's assume 3 for now). If the sensor output is HIGH, then there is error. If the sensor output is LOW, then there is no error. The design is that if any of the sensor detec... |
H: VHDL design: why my integer goes by the number of bits and not the value?
I am trying to build pwm in wave form .meaning for exmaple I want the pwm go for 5 rising edge on and then 5 rising edges off . But for some reason when I write :
variable counter_test : integer range 0 to 10 ;
meaning that variable co... |
H: What is the use of a capacitor in a DC motor circuit?
I'm trying to understand all the components I need in order to drive a DC motor through an Arduino.
I saw this circuit below, which has a capacitor (other sources show same circuit but without the capacitor).
I understand that the resistor is a pull-down to evac... |
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