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H: Why does this 75C battery only have a 12 gauge wire on it?
Example battery:
https://www.amazon.com/Lectron-Pro-7-4V-7600mAh-Battery/dp/B01AAVM1MS
I see many different RC batteries that are have very High "C" ratings but all of them use connectors rated for very low current. According to the formula the continuous c... |
H: What is the smallest metal object you can ground yourself with?
Say I am installing a new CPU in my desktop motherboard and I am interested in grounding myself (by touch or one of those nifty bracelets) to avoid damaging my components.
What is the nature of grounding? Does grounding effectiveness correlated to the ... |
H: Can I decrease the width of microstrip at the pin?
I am trying to connect a 60 mil microstrip to the pin of IC. However, the width is relatively large to the space between pins on the IC. Can I decrease the width of microstrip where I connect it to the pin, so that it can be no clearance error?
In addition, when I... |
H: Tesla coil, where do the sparks from the secondary coil ground to?
This might be an obvious question, but I was wondering how a Tesla coil emits sparks that's seem to complete a circuit in thin air, and how one end of the secondary completes a circuit with the other side of the secondary. Is this circuit simply bei... |
H: Auto Gain control circuit idea
I am trying to make an Auto Gain control circuit.
Having any input source's voltage the same.
For example my latop outputs around 1.36Vrms @ 1khz
and my iPhone outputs around 0.962Vrms @ 1khz
Regardless of input source I want the input voltage to be around the same as the laptops.
T... |
H: How to sense voltage of 48 V 600 Ah VRLA battery bank for Arduino
How to check the battery terminal voltage across 48 V (2* 24 V cells) of VRLA battery bank (600 Ah). I am not sure whether a voltage divider serves the purpose. Please give me the advice to convert it to 5 V (Arduino compatible).
AI: A voltage divide... |
H: Meaning of the "pole" of a transfer function with time delay
I learned in basic control theory that we can determine the stability of an LTI system by the signs of the real part of the poles of its transfer function \$H(s)=\frac{N(s)}{D(s)}\$. For a rational system, where both \$N(s)\$ and \$D(s)\$ are polynomials ... |
H: Voltage divider with ac source
Left side of the voltage divider is a bit confusing. How would AC react with DC voltage?
Considering a high frequency ac source, capacitor would act as a wire. So what will be the output voltage?
Logical answer instead of a mathematical one would be more appreciable.
AI: Vout would b... |
H: understanding of UART , if two devices share a common ground. How do they get to the same voltage level for a save data transmission?
My question is related to the common ground in a UART communication.
So far, what I understand how communication in general works is: Distinguishing the voltage between two cables (o... |
H: Input bias current compensation
I am studying the Input Bias Current compensation technique by connecting the resistor to non inverting terminal of opamp. why the reistor of bias compensation should be parallel value of Rf & Ri ? the other end of Rf and Ri is not same and voltage produced by bias current in Rf and ... |
H: How are glass diodes produced?
What I am trying to understand is how the diode is placed inside of the encapsulating glass container such as that pictured in the following:
I've tried to read some patents, where I more or less couldn't understand any of the language. How do manufacturers get the glass to encapsula... |
H: Calculation of Microstrip Width
I am confused by the "substrate height" and "trace thickness" when I am calculating my microstrip width on here . From manufacturer, I got Does the "out layer copper thickness" refer to "trace thickness" and "inner layer copper thickness" refer to "substrate height"? The board is FR4... |
H: Problem with voltage between a DC step up and Raspberry
I am working with a DC step up (XL6009) and a battery for the cell phone (3.8V), with a capacity of 2800mAh to power a Raspberry (10 minutes maximum). The output voltage of this module (XL6009) can be regulated by a trimmer (included), granting an output range... |
H: Parallel EEPROM write to with I2C
I was wondering if there is a hybrid between the serial and parallel EEPROM's? What I mean is, is there an EEPROM that can be written to over I2C and then once it is setup can be controlled with some hardware Address pins, like how parallel EEPROM's change there output pin states w... |
H: What happens when a motor is spun faster than its rated RPM from an external force?
I've seen plenty of questions wondering what happens when voltage is applied that would exceed the RPM rating, but what happens on the voltage/current side when something external - the wind spinning blades attached to the motor - s... |
H: Passive reset circuit for multi-chip game design
I've been building a small handheld gaming device based around the ATTiny85 and an SSD1306 OLED screen. It's a very limited system and as such I needed to be creative about how I used the I/O pins. I asked a question for replacing the SSD1306 reset logic with passive... |
H: How to create variable power source circuit from a battery source?
Basically, I have a high drain battery at 3.7v and I want the output power to be controllable. The circuit I have designed so far is a boost DC-DC converter using a 555 timer to control the switching mosfet, and a homemade inductor, and all the nece... |
H: Why solder mask are not applied to RF PCBs
I've gone through some of the RF PCB designs. In which solder masking on the traces are not present. Like this one
Is there a specific reason or performance issue to remove that?
AI: There are several reasons.
1) Soldermask is lossy, and different types of mask are differ... |
H: VHDL/FPGA Tacho Pulse Counter
I am attempting to implement a tachometer interface that will accept digital pulses as an input. I simply count clk rising edges (50Mhz) between each rising edge of the tacho pulses (1Mhz). I have found examples on the web that achieve what I need to do, but in an attempt to not make t... |
H: Old Radio Colpitts Oscillator? Or not?
I am a beginner hobbyist form Brasil, posting here for the first time.
I am trying to understand the schematic of an old Transglobe radio that my late grandfather gave me. It motivates me to learn more of analog electronics.
After searching the internet for oscillators, it app... |
H: Does a pickup microphone work in space (vacuum)?
Of course in space there is no sound transmitted via air, so there is no air-borne sound, but there is structure borne sound. This sound can be recorded with a pickup microphone, but do pickup microphones need air to work as well?
Considering that a pickup is really ... |
H: HIGH in input pin without connect
I declare pin 12 as input mode in Arduino UNO. I didn't connect to that pin 12 but if I read state of that pin, the result is always HIGH. I want to avoid that. I made several googling but I don't get cool answer.
AI: Why are you reading that pin? If the intention is to detect an e... |
H: How does the inductor have an initial condition in this circuit?
If the initial current in the inductor is \$i(0^+)= 0 A \$ why is it that when the switch occurs the initial voltage in the inductor is \$ V_L(0^+)=121.4 V\$
AI: The circuit you have is this:
simulate this circuit – Schematic created using CircuitLab... |
H: Looking for external watchdog chip for Raspberry Pi 3 model B board
I'm working on a project that has chosen an RPi3 model B board as part of the system. We previously had an external watchdog system that would cut the entire system power if the watchdog expired. This external watchdog system has been "optimized ... |
H: OPAMP saturating when output is negative, simulation is OK
The schematics:
It should convert 0-3.3V input from the DAC to -4.1 + 4.1V (roughly)
The positive part works great, the negative output voltage saturates at -2.95V.
Is it ok? The simulation looks ok (and it is the expected behavior):
The part: https://www... |
H: Why LME49710 does not perform at least as good as LM358 for audio mic op-amp?
I built a hobby mic op-amp circuit as described here:
It gave me a pretty ok result:
Now I replaced LM358 with LME49710. The circuit is the same, except from the wiring to the LME49710 pins (LM358 pin 1 is the output while it's pin 6 on... |
H: Is there such a thing as a fully differential line driver?
I'm looking to find something similar to the TI drv134 (http://www.ti.com/lit/ds/symlink/drv134.pdf), but then with differential inputs instead of single ended.
Is there even such a thing? I can't seem to find it.
I can of course easily place an opamp befo... |
H: Basic Op Amp Circuit
I am reading "Intuitive IC Op Amps" by Frederiksen and getting stuck on one of the basic circuits. The book presents this image as a simple proxy for an op-amp.
Can someone help me understand a few things:
1) How is the Input biasing current and Output biasing current selected? What simple BJT... |
H: Inductor degradation?
For SMPS, I would like to know if inductors degrade with time and frequent high current usage. The idea of this, is to determine the elements that are most likely to fail over time in a SMPS (for example electrolytic capacitors), so I can make them easily replaceable in my PCB. Thank you
AI: T... |
H: Modbus RTU Implementation to Automate Temperature through PIC Microcontroller
I would like some help about implementing the Modbus RTU communications protocol in an automated system that I am trying to develop. I am confused about how to generally set up my network because I have never used modbus and am generally ... |
H: E fields and M fields in Near Field
I am reading a textbook that mentions that small loops with high dI/dt on a PCB tend to produce predominantly magnetic waves and stubs with high dV/dt tend to produce predominantly electric waves in the near field. In the far field, both radiators result in EM waves.
1) I don't u... |
H: Drawing DC current from batteries on charge controller
I have an off-grid solar system where this inverter/charge controller (ICC) is connected to a 48V battery (which is in fact 2 parallel quartets of 12V batteries, but this is non-relevant detail I guess). The ICC would feed current to the battery at as high as 5... |
H: Can a system with more than 180 phase lag ever be stable?
For a system to be stable you must not reach a phase of 180 degrees before gain reaches 1 (for an ideal system). The layman explanation I was offered was that otherwise, your negative feedback becomes positive and you just built an oscillator.
What if you cr... |
H: Getting Accelerometer values from MPU 6050
I m trying to read accelerometer values from mpu 6050 in atmega328p (Arduino UNO). I want an embedded c program that's why don't wanna use any external lib. So I read about I2C protocol, read the datasheet of MPU 6050, register sheet of MPU 6050 and developed a code as per... |
H: A globe from a torch and a refrigerator bulb are connected in series across a power supply. Predict what would happen?
A globe from a torch (rated at 6V, 0.5 amp) and a refrigerator bulb (rated 240V, 10W) are connected in series across a 240V power supply. Predict what would happen?
I understand that the torch glob... |
H: Pin letters not shown in circular connectors D38999 series
I'm working with military circular connectors of the D38999 series and I've discovered that when the connectors have their pins designated by letters instead of numbers, some letters are not shown.
For example, in this image, the letter "O" is not shown:
... |
H: How to find the value of alpha in this curcuit?
I have tried to solve this way but i am not sure how to proceed from here:
[![tried solution][2]][2]
AI: You have a \$9\:\text{A}\$ current source that leaves from the top end by only two paths and arrives to the bottom end via only two paths. You have two unknowns, ... |
H: Photovoltaic/solar power supply for Raspberry Pi
I want to build a power supply for my Raspberry Pi zero. It needs 5V and 2.5A (2A also working but only if 2.5A is not possible).
I want to use solar cells to get the 5V and 2.5A. I have already searched amazon for solar panels but somehow the ones I've found do only... |
H: Identification of SMD component
could someone please help me to identify what is long white SMD with JR marking? I am trying to draw a schematics for better understandig how ethernet and PoE on this device is implemented.
It has near zero resistance and i could not google anything with JR marking witch would have t... |
H: LED Dimmer only using NPN BJT and potentiometer
Does this circuit looks ok?
I'm trying to make a RGB lamp with knob controls. The LED has a maximum current of 20mA. I've successfully created a working prototype of below circuit.
I'm not from electronics background (hence for me priority wise simplicity of circuit... |
H: Strange footprint labeled PJ## on laptop's motherboard
Today I came across a picture of a laptop motherboar (below).
I noticed three strange looking small footprints, labelled PJ12, PJ36 and PJ37.
The J may stand for jumper, and on the top left corner there is a PJ8 that appears to be covered with a blob of solder.... |
H: How to test for shorts on a breakout?
Working on LoRa project with the RFM95W. Most online resources like 1 and 2 suggest using a PCB since the module itself is quite small and hard to work with; but where's the fun (and learning) in that!
After soldering it looks like: (it isn't meant to be deployed, just testing... |
H: Why do most rotary potentiometers have an opening?
Is this opening not a bad thing because dust can get in? I'm thinking about putting a piece of tape on it.
AI: I think it is to do with manufacturing process. Most low cost pots have a carbon track that has been deposited onto some kind of fibre board, which the wi... |
H: Designing an IoT product
This is more of a general question of the embedded electronics industry. At the moment I'm planning on building a device with a similar requirement to the Nest products. Essentially, I want to have a WiFi hotspot from this device that I can connect to with a nice browser UI and can see live... |
H: How much energy is required to charge a battery to 50% vs 100%?
When I go hiking, I only recharge my phone to about 80% from my backup supply because I know it gets harder and harder to push more energy into a battery the closer it gets to full capacity. So I am roughly assuming I could charge my phone a few times... |
H: Data acquisition and sending with different speed
I need to read certain physical parameters through the sensors and send them to the microcontroller and microcontroller should combine this information and send through rf transmitter. I can read all the analog parameters using ADC. There is PWM signal coming from t... |
H: Compact thermostat for VCO temperature stability
So I have a voltage controlled oscillator with an exponential input made using the THAT2181 VCA IC. The schematic is shown below - the THAT2181 IC is used to change the C4 capacitor charging current and, therefore, the output frequency depending on the LOWCV input.
T... |
H: RL filter output attenuation
I am designing high pass RL filter. R is 550 [Ohm], L is 220 [uH]. I calculated that time constant is therefore 0.0000004 [s] and -3 dB pulsation 2 500 000 and frequency 397 887 [Hz]. I put this on the breadboard and connected JDS 6600 signal generator and Rigol DS1054Z oscilloscope to ... |
H: Understanding the resistance readings between PCB connectors
Based on a question I asked earlier today, I am trying to verify that there's not short caused by my bad soldering.
Luckily I had bought two of these modules. To make a baseline, I started looking at the module that I had not done anything to.
Using this... |
H: Why do cascading D-Flip Flops prevent metastability?
I understand what metastability is but don't understand how linking together flip flops reduces this?
If the output of the first flipflop is metastable, this gets used as input for the second one. But I don't see how the 2nd flip flop will be able to do anything ... |
H: Window Comparator
I am reading this website and don't understand why this circuit doesn't blow up. If Vin = Vcc then seems to me top opamp A1 would drive low (Vcc > 2/3Vcc and inverting comparator) and the bottom one A2 would drive high (Vcc > 1/3Vcc and non-inverting comparator). So now you have two opamps driving... |
H: Square wave to DC voltage with passive components
Good day,
I have a design challenge that I have been thinking about.
Is there a passive and inexpensive system that I can get a square wave (frequency not decided yet, but less than 8MHz) that will output a 5V DC signal? If the input changes to a fixed voltage the o... |
H: How to divide complex number in VHDL?
I know how to divide numbers in VHDL (or using one of the Xilinx IP core generators) but I do not know how to do it in the case the numbers are complex.
In my case I have defined a complex number as this:
type complex12 is record
re : std_logic_vector (11 downto 0);
im... |
H: Large LED Array powered via USB
I am working on building a keyboard at the moment and I have run into an issue.
I need to power 79 led backlights on the keyboard but I have no idea how to do this given that the power is coming via usb. I know usb 3 can handle up to 900ma but I want to make this work on all usb. S... |
H: Limiting current for Peltier
We are building a greenhouse box for strawberry plant. We need to control the humidity and temperature inside the box. We need to maintain in range of 23 - 18 degree Celcius and humidity in range of 68 - 73 %. So we arrange the peltier in parallel and also the fan in parallel. We have a... |
H: 128-bit data UART
I have made a UART controller in VHDL (transmitter, receiver and a FIFO for each component) and I'd like to send/receive 128 bits of data.
Is there anything that prevent me from implementing a 128-bit FIFO, and send/receive 130-bit UART frames ? Or should I send/receive 16 frames of 10 bits (8 bi... |
H: LED blinking while loop not working AVR timer 0
It is strange and rare. I am trying to blink a LED at PD0 at 2hz, but it doesn't work. Seems to me that while loop doesn't work at all. I have triple checked the code. what is the problem here?
uint8_t c=0;
int main(void){
DDRD= 1<<0 ;
TCCR0 = (1 << CS02) | (1 << ... |
H: MOSFET as switches in non ohmic region
I have a project in which I have to "close a digital switch" using either a 5V or a 3.3V supply. The load will be at 12V, with a required current of around 200mA.
As a newbie I thought to use an N-channel MOSFET such as the FQP30N06L datasheet.
While the transistor will actual... |
H: kVA calculations
For electrical panels / systems with three phase electricity (red, yellow, blue) ~220/127.
When using line to line we get 220 V is this considered single phase system or three phase?
I know three phase devices such as motors use all three phases together, this is clearly three phase and we use thre... |
H: LP311 collector remains at ~11V when "low"
Okay,
I'm trying to monitor current going to a device, and in case current is drawn, light a led and provide a low signal (<5V) to a microcontroller.
The current goes through a half-ohm resistor and the voltage difference is amplified by AD8210. Output of the amplifier is ... |
H: PNP instead of NPN in series voltage regulator
I have a question regarding PNP transistor, since I am not very familiar with it. What would be the difference in the circuit below, if we switched NPN to PNP?
Right now the output voltage is equal to \$U_D\cdot\left(1+\frac{R_4}{R_4}\right)\$
The value of \$R_1\$ is ... |
H: Power indicator for circuits with voltages much higher than LED forward voltages (say 15-48V)
I have a circuit that has a 24V power rail and I put an LED and series resistor on it for power indication. Even at 10mA forward current, over 200mW of power is dissipated, over 90% of it in the series resistor. This is mo... |
H: Why do we use Laplace transforms to analyse transient circuits?
I just learned transient circuits and we solved them both in the time domain and the Laplace domain and I can't understand why we would use the Laplace domain as it seems it is a lot more simple to use the time domain especially in series RLC circuits.... |
H: PIR Sensor triggering voltage not enough
I'm using a HC-SR501 PIR sensor.
The sensor is working fine, it outputs 3.3 V on motion detection.
But when I connect the PIR sensor to pin 2 (interrupt) of an Arduino pro mini,
the voltage output is only 0.289 V on motion detection.
The sensor is detecting motion, it's just... |
H: Vias Size for Microstrip
if my microstrip trace width is about 50 mil, how large should my via drill size be? Should it also be around 50 mil? Thanks!
AI: You can design your via to minimize the discontinuity it introduces in your transmission line.
Basically this means balancing the inductance introduced by the vi... |
H: measure Watts, given only Current in a single-phase AC system
I live in Greece where 220Volts/50 Hz is in every house's socket.
I need to measure the Watts being consumed by a device (a single lamp), which I hook up in the socket.
The problem is that I can only measure the instantaneous current i(t). I don't know t... |
H: CMOS NAND Image
I was looking at this image which shows a CMOS NAND standard cell.
However, how can I see this depicts a NAND?
A CMOS NAND has parallel PMOS and serial NMOS transistors but somehow I can't see this in this image. Any explaination?
AI: I've put a picture of the ciruit below:
blue/violet ... metal ... |
H: Confusion about inductors in series vs. combined
I suddenly was getting confused while reading about inductors. The formula for inductance I was using was the one like in the answer to this question. However, I have also read that the inductance of inductors in series is the sum of the inductances (like with resi... |
H: What kind component is this?
What kind of component is this? And is that crack normal or is it a sign that it's bad?
AI: Spark Gap over voltage protector.
Here is another E.SE question relating to a similar air gap component.
The component could also incorporate a capacitor or MOV (metal oxide varistor) that the le... |
H: How to program ATmega8U2
I was given an ATmega8U2 chip by my friend and I have been doing a bit of research about it. It says it does not come with a pre-programmed with a boot loader, so I was just interested about how to go about getting a c program on there? Do I have to download a boot loader to the chip or so... |
H: Root locus, where do they leave the line parallel to imaginary axis
I know how to sketch by hand root locus of simpler systems. Consider the root locus which Matlab gives for:
$$G(s) = \frac{1}{(s+4)(s+6)(s^2 + 10s + 100)}$$
I've marked the points of interest P1 and P2. When the following task was done during clas... |
H: MPLAB X XC32 - Peculiar build issue involving volatile variables
I am struggling with an issue that is already costing me 2 days of productive work.
The code of main.c at the end of the question is a stripped-down version of the entire project, and contains the relevant code related to the issue discussed.
A brief ... |
H: What is the point of Geiger counter calibration?
I understand that the three ways Geiger counters can be calibrated are electronic calibration and energy calibration, which both use a pulse generator, and radiological calibration which uses a check source.
Electronic calibration simply involves sending pulses to th... |
H: question about Vivado synthesis and implementation
I use Vivado to program my Basys-3 card and I have a quick question about Synthesis and implementation. I noticed that when Vivado knows the inputs of an entity, it calculates the result directly and this calculation is not done on the FPGA core.
For example, I ha... |
H: Optimization of Vivado synthesis
I am currently using Vivado to develop several FPGA designs, and I am wondering if the components numbers given during Synthesis are optimal. I mean, are there some ways to optimize the synthesis, in order for example to reduce the number of LUT or FF used by the FPGA ?
AI: They are... |
H: How was this formula of voltage on capacitor achieved?
We know that voltage across a capacitor is given by
But there is this other formula
How this second formula was deducted mathematically from the first one? or from another one?
AI: Let I_r be current in the resistor = Vc/R at any time.
Vc = Q/C from the basi... |
H: What does "minimum etch technique" refer to in PCB layout/design?
in the application hints for an ADC (AD7927 page 26) it says:
The printed circuit board that houses the AD7927 should be
designed such that the analog and digital sections are separated
and confined to certain areas of the board. This facilitate... |
H: Why does my LED strip list maximum power as 45W while the LEDs added makes 37.5W?
My 5-meter LED strip with 30 WS2812B per meter lists "Maximum power: 45W". However, if I calculate it I get:
WS2812B max current draw * voltage * number of LEDs
= 50 mA * 5 V * 150
= 37.5 W
Is the rest of the power due to voltage dro... |
H: Can anyone ID this 3 pin plug?
This connector is out of a Sega Dreamcast. I need a new wiring harness but can't find out what this plug is.
The plug is 6.54mm wide, 3.42mm high (excluding the "key" 4.08 with the key), 6.48mm deep.
I can just about make out the letters JST, but very small. I can't get the camera... |
H: What is a reasonable way to connect small wires?
These wires will carry up to 1.5A at 5V outdoors in clear weather. Would it be reasonable to connect them by simply taping them together with electrical tape?
I'm new to electronics outside of embedded programming and simple Arduino prototyping, so I wanted to check... |
H: Equivalent Inductor Equation (Antoniou Gyrator Proof)
I've been working on a proof for University and I've been able to understand most of what I was asked, but I'm having trouble understanding why is it that the equivalent inductor in an Antoniou Gyrator has inductance L = (R1*R3*R5*C4)/R2, referring to the image ... |
H: Operational Amplifier Integator
I want to design op amp integrator circuit with variable time constant using a simple switch. What is the typical shunt capacitance of a switch? I assume Ron of switch to be less than 5 Ohms. I want switch to minimally effect overall feedback capacitance. I am not worried about trans... |
H: Why use DDR instead of increasing clock speed?
Why would you want to use DDR ram and read/write on every rising and falling edge of the clock instead of just doubling your clock speed and read/write on just one of either the rising or falling edge?
Are there pros and cons to each?
AI: With SDR, there are two clock ... |
H: What is the best way to search components
I am a student of Electronic Engineering and right now I am doing my practicing in a company. When I was in the university, I have no problem searching a component, but here in the company needs sometimes normal elements (Level Converters, resistors, capacitance, Reductor D... |
H: Examine rectified voltage before and after
I built a simple bridge rectifier.
simulate this circuit – Schematic created using CircuitLab
I connected the output of the function generator with CH1 of my oscilloscope and
with the input of the rectifier (using a T-Piece). The output goes into CH2.
The original wave ... |
H: Need help to find replacement for power mosfet IRF7303
I have to design a voltage regulator circuit using DC-DC controller MAX1655.
Required voltage output from the circuit is 3.3V at 2A (circuit is shown at page 10 of datasheet).
According to the datasheet for MAX1655 (at page no- 11) i have to use IRF7303 or NDS8... |
H: LM833N OP AMP Configuration Help
I am using this Chip: LM833N
to essentially trying to Half Wave rectify my low AC signal input ~1.36Vp.
Using it in this configuration for now to get things started (Ignore the part number).
CH1 is the input and CH2 is the output, noted this is while the OP AMP is turned off. (I... |
H: reverse engineering the Nord Lead 4 control board
I am reverse engineering a synthesizer named nord lead 4. I want to tap in between the control board and mainboard which has the microprocessor.
i didn’t started with the powered on analysis but i am making a map of the connections and getting to know the IC’s.
I fi... |
H: Noise on the whole board after USB connection
I designed a device on which there is a HUB, FT232 , two external USB port and some periphery.
I wanted to check the noise on the power bus. And I saw only white noise.
But after I connect the USB cable, I see on ALL circuit this is an noise.
Most likely it is common... |
H: Large amount of heat generated by AC to DC power supply
I purchased this power supply:
https://www.amazon.com/Yes-Original-Power-Supply-Security-Camera/dp/B078MN4XQG/ref=sr_1_3?ie=UTF8&qid=1530044862&sr=8-3&keywords=CCTV+Security+Camera+18CH+12V+15A+180W&dpID=51SEIcuz4xL&preST=_SX300_QL70_&dpSrc=srch
I am running a... |
H: Measuring Current Using A Resistor?
Sometimes in videos made by the YouTube creator ElectroBOOM the creator says he is using a 1 ohm series resistor to measure current. I looked it up and found some links to forums where people are saying that you can use a resistor rather than a DMM to measure current, but I can't... |
H: Verify bias voltage with no load
I have a device that can be configured to maintain a specific bias voltage on the output. How should I verify if it actually generates that specific voltage?
I do not think I could simply use a multimeter to measure that voltage. Instead, I thought I should use a resistor on the out... |
H: variable regulation source
I am learning electronics and I want to make a , variable regulation source for a soldering iron, which works at 50W, how much voltage and amps should have the output? For the soldering iron works correctly
AI: Every Load has its recommended applied power. Some works by applying AC volta... |
H: Measuring crystal drive strength without a current probe
TL;DR
Is there a means of measuring the crystal drive level reliably using voltage measurements (even with a differential voltage probe)?
Background:
I am attempting to measure the crystal drive strength in order to ensure that it is not exceeding its rated ... |
H: Relay model for controlling the Air Conditioner power supply
I am trying to control my Air conditioner via MQTT protocol. I just want to make the power on and off. How can I calculate the relay current rating for 1126 Watts of power?
Link to AC model: https://www.amazon.in/Voltas-1-2-Split-155-CY/dp/B00LWRDJEE
Also... |
H: How can I replace an electret microphone with a dynamic microphone in the Velleman voice changer circuit?
I am attempting to build the MK171 Velleman voice changer, but with a 1/4" microphone socket for a dynamic microphone instead of the electret microphone which is attached to the board as standard.
I've done som... |
H: Why is the output voltage of this circuit is changing in simulation?
Circuit 1:
Circuit 2:
The only difference between Circuit 1 and Circuit 2 is`that in Circuit 2 a parallel 2.2k resistor R8 is added as a load next to R6.
Why adding this R8 is halving the output voltage here?
I tested this in real with a scope,... |
H: Safety of Using USB Charger
I am looking at getting a 3 port USB wall charger, to save having so many individual ones plugged in. A lot that I've seen offer Qualcomm FastCharge, and other similar things, which are around 2.4A, or higher.
The chargers that I currently have (which are cheap ones) are alll 1A or less ... |
H: why does this approach neglect the output resistance of the bjt in calculating gain?
This is the question that I would like to ask about. My question is with regards to finding Vc for question 3. This is the memo for the question:
However, I have a problem with regard to how they find Vc. Surely, if Vc is equal t... |
H: Triac optocoupler circuit
I am working with this circuit:
I am using a snubberless triac (BTA216X) and hence I am getting rid of snubber circuit (39 ohm res and 0.01 uF cap circled in red). Am I right in doing so?
Besides this, can I get rid of 330 ohm resistor circled in blue? As per my understanding, it works li... |
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