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H: Power cable for 5V 20A power supply?
I bought a switching power dupply (SMPS) rated at 5V | 20A | 100W.
But it seems I don't understand how power supply works. I need total of 18A on output, but that seems to be over the limit of standard 16A | 220V wall outlet's limit.
How would I power this supply without burn... |
H: RS232 serial output: confusion with wiring
Brace with me as I am new to electronics, but am also eager to learn. I have a sensor which has 4 un-terminated wires:
1) 12V to 24V
2) RS-232 TxD
3) RS-232 RxD
4) Ground(and serial connector return)
I'm trying to get the sensor and my computer to talk but have faced nothi... |
H: If Conventional Current is wrong, how can I trace the flow of current in a schematic?
If Conventional Current is backwards, how do I look at something like this schematic and trace the flow of current? I'd like to follow the design linearly from positive to negative.
When the battery is on, does current go to 8, ... |
H: Saturation Point of a magnet given some Parameters
I know from my hard magnets (the remanent magnetization is very close to the saturated magnetization) the Coercivity \$h_c\$, the energy product \$B-H\$ and the remanent magnetization \$m_{rs}\$. Is it possible to estimate the value for the saturation field that I ... |
H: Self-clocking driver / transceiver
I'm looking for a way to transmit a clock signal and data over a single line,
perhaps using a self-clocking signal such as Manchester coding.
The design I'm working on has a number of chained units, with data fed into the first unit in the chain and passed along to subsequent dev... |
H: Would the Bluegigga WT12 be suitable for a battery powered application?
I understand that the Bluegigga WT12 requires RS232 when using UART which is what I'm planning to do and thus it requires high voltages? Would that make it unsuitable for a battery powered application? If not what alternative Bluetooth module c... |
H: How do I power/wire something that is rotating constantly WITHOUT extra batteries?
So I want to make a Lazy Susan that is rotating constantly in one direction. I also want to have some other things on top such as neon signs, moving things, and etc. Problem is I want this to all run off of one DC source. Problem is ... |
H: If one of the resistors becomes open circuited, what is the power
Question: The total power in a parallel circuit with four resistors of equal value is 570W. If one of the resistors becomes open circuited, what is the power dissipated by each of the remaining resistors?
My Attempt:
\$P_1 + P_2 + P_3 + P_4 = 570\$
\... |
H: Switching a 12V AC current from a microcontroller (no magnetic relay)
I need to commute on/off a coil feeded with 12 Vac from a microcontroller output (5V).
I've found a cheap Solid State Relay but the datasheet and a forum says this doesn't work with less than 75 Volts ac.
G3MB-202P SSR
https://www.electronicas... |
H: How do I prevent bridges while soldering SMD Components?
I have noticed that whenever I try to solder a component with many pins close together (like an IC), I get tiny bridges of solder, which shorts the pins. Is there any easy way to solder SMDs without solder bridges?
AI: When soldering by hand, it is easier and... |
H: Unexpected bits when shifting out (ATtiny85)
I'm trying to spoof a 433 MHz remote and I have a sequence of 32 bytes that I want to repeatedly shift out to one of ATtiny85's pins. The signal then goes to a cheap Chinese-type 433 Mhz transmitter.
I utilized the built-in 8-bit Timer/Counter0. Unfortunately, in constan... |
H: Using Fourier transform to solve current in a circuit with initial condition
I am trying to solve the inductor current for the circuit below by using Fourier transform instead of Laplace.
The purpose is to see if Fourier transform also works for problems with initial conditions like this.
The voltage source is a D... |
H: How to interface the HX711 Weight Scale ADC with a microcontroller?
In my project I need to interface HX711 24 bit External ADC to STM32L100RC6 MCU
How can I do this ?
AI: I've used this IC in several designs. It's quite simple, but a bit ad hoc: you connect DOUT and PD_SCK to 2 GPIOs of your MCU. Data comes out o... |
H: In a single diode rectifier circuit, is capacitor offering additional energy to Load?
I am a graduate student majoring in electrical engineering.
Now, I am studying about wireless power transfer and energy harvesting.
While reading a paper written by Bruno Clerckx, who is senior member at IEEE, I encountered someth... |
H: VHDL Knight Rider
I am newbie in VHDL. In my code, everything seems right but code doesn't work properly. I couldn't find where my fault is. Any solutions?
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity Knight_Rider is
port (
in_CLK: in std_logic;
out_LED... |
H: How can I determine maximum load current limit of DC-DC step up switch regulator?
I have a trouble in designing power supply for my device.
I've shifted 3.3V up to 5v by using LMR 62421 manufactured by Texas Instruments. I'm planning to use the 5v rail to power my devices(module, sensor, etc...) Everything is fine ... |
H: High speed parameters for transistor
How to choose a Bipolar Junction Transistor (BJT) for a switching frequency of 400KHz.
AI: If I would get a transistor to switch at 400 kHz, then I would look for a transistor with a bandwidth of at least 400 kHz, I'd probably look for a transistor with 1 MHz for some margin bec... |
H: Voltage converter (220V to 110V) with surge protector power strip—how much wattage do I need, and is it safe?
For the next 6 months, I'll be living in a country where the voltage is 220V. The risk of frying electronics is also much higher there, so I want to get a surge protector. I've been researching this for the... |
H: Altium high current trace
I'm designing a PCB in Altium and I need to trace tracks that can support 20A. I used a PCB Track Width Calculator and I need a width of 10mm for my tracks. The problem is, how do you link the pads of component to such a large trace?
Can I make a small trace at the end of the large one? D... |
H: What is the efficiency of a stepper motor driver?
We are using this stepper motor driver (https://www.sparkfun.com/products/12779). In its datasheet, there is no mention of efficiency? How much is the efficiency in motor drivers like these?
AI: In motion control efficiency is usually mechanical output power (w*T) d... |
H: Dynamic Braking resistor chopper circuit
I want to design a standalone dynamic braking circuit for AC motor driver , because to deal with regenerative energy that the AC source cannot handle causing a DC bus voltage Rise . The concept is well established in many resources online that senses the DC bus voltage and d... |
H: Why is the plastic around my battery terminal melting?
I am using 2 dry batteries for my backup UPS. For some reason the plastic around one of the terminals of a battery is melting and producing a lot of smell. Most of the times it works fine but at some odd days, whenever we put load on the batteries/UPS, it start... |
H: Can I use a transimpedance amplifier using current through a resistor?
I'm designing a lab exercise for 1st year circuits students. They learn about current controlled voltage sources, but we never show them one. I know that transimpedance amplifiers are used for this purpose, but I've only seen them used with de... |
H: Is cable to resistor also considered a resistor?
I have a parallel circuit with 50 parallel wires each connected to main cables (+ and -) on top and bottom side of the circuit. I want to calculate the total resistance which I know is R = R1/ total number of parallel wires.
Should I also include main cables in my ca... |
H: Set array of wires to integer value in Verilog test bench
I am writing a test bench for a module that takes an array of inputs that represents a number using the following code:
module ComparatorTest;
wire [3:0] a;
wire [3:0] b;
output aHigher, bHigher, equal;
Comparator c (a, b, aHigher, bHigher, equal);
initial... |
H: Can a modern multimeter be classified as a discrete component tester?
I work for an avionics training company where we are required to meet certain criteria with respect to the theory and practical tasks that we teach. At the moment there is one area of debate with respect to a requirement for us to teach the use o... |
H: DC Voltage Polarity and Current Flow?
So I'm getting pretty familiar with Electrical Theory but one issue keeps bringing me problems. In a DC circuit, there is a negative (-) and a positive (+). I am aware that in electron flow theory, current flows from the negative (-) to positive (+). See Figure 1.
But in a car... |
H: Need circuit to toggle voltage between two paths
I need to create a circuit to allow me to toggle a source voltage from one path to another. I need to be able to toggle the path from the first path to the second while a second voltage is active, and go back to the first path when the second voltage is not active, s... |
H: BJT Transistor Amplifiers
Why the input voltage to the amplifier in the circuit on right side is taken from resistor R2 when circuit on the left side is doing the same job with just one resistor (Rin). Why to use the voltage divider circuit to provide the input to the input of an amplifier ?
AI: If you remember th... |
H: Would a stepper motor driver chop a high current to its max allowable limit efficiently everytime?
We are using this stepper motor driver A3967(https://www.sparkfun.com/products/12779). If we increase the input current to the driver to 2Amp, will it cutoff the current to the motor at 750mA everytime since it is a c... |
H: Is thinner solder better?
I have a few types of solder. One of them is 0.4 mm and the other is around 0.8 (not very sure). Which one should I use for SMD, and which is good for general purpose?
I have heard that it is best to learn with a thinner wire. Is this true?
AI: The primary way of controlling how much sold... |
H: Altium Designer 3D collision/distance problem
I'm using Altium designer 17 and I want to make a 3D layout of my board.
My only problem is that whenever I place a piece on the pcb, the component is flashing green and it says Collision. It Collision even if nothing is touching the pcb. Exemple this transfo:
AI: It so... |
H: Voltage Generator with Full Wave Rectifier
I have simulated a circuit which gives +12V and -12VDC output. I am planning to obtain input signals from a transformer. I have some questions related to it, if you share your ideas i will be very happy. I used LM7812, LM7912 regulators and S1M diodes.
There is a delay a... |
H: Baking SMD integrated circuits for prolong time
I recieved samples of AD7175-2 and AD5684R with an instruction:
If these samples are to be subjected to solder reflow or high temperature process, they must be baked for 24 hours at 125°C prior board mount. Failure to comply may result in crack and/or delamination of... |
H: Missing pads allowed on BGA?
I'd like to use a 0.35mm BGA in a new design. If possible, I'd like to do this without resorting to an expensive manufacturing process with microvias. This is possible for my particular application, if I can pull a little trick.
All of the pads I need for my application are around the p... |
H: Wrong load capacitance for 20 MHz, 20 pf crystal
I am new to microcontroller development, and I wanted to try running the MSP430f5529 off of an external crystal of 20 MHz that requires 20 pF of capacitance. I read on the datasheet that the pins can support up to 12 pF of internal capacitance, which is what I planne... |
H: Configure UCSCTL0 register MSP430F5529
First off: I'm brand new to microcontroller development, so please forgive me for the simple question. I'm trying to learn for my FIRST robotics team so we can use the MSP430 to handle some extra sensors.
I'm working on understanding/configuring the Unified Clock System. I wa... |
H: What is the terminal labelled "U" in some autotransformers?
I'm trying to wire an autotransformer for usage as a speed controller for a brushless motor fan.
The terminals are quite self explanatory:
Pe for ground, L-N are my input, N1-L1 are unregulated output (same as L-N) and U-N are the output to my motor. Havi... |
H: Opamp input voltage divider creates wrong voltage - what could be the cause?
I'm using above 1:2 differential opamp, when 72V applied to the 30:1 voltage divider, voltage across R1 is only 1.727V instead of 2.4V, opamp output is around 3.4V.
Opamp is LMC6062IN/NOPB
http://www.ti.com/lit/ds/symlink/lmc6062.pdf
I t... |
H: Configuring BLDC motor for low-speed application
Given: I need to the simulate sinusoidal forces on a wind-tunnel model using a bench-top setup. I've designed a rig where I spin a load at high speeds to generate centrifugal centripetal forces, and those forces--which will periodically align completely in the X, Y, ... |
H: SPI: MOSI not dropping LOW for receiving device
I hope this question is not a repeat of others on this stack exchange concerning SPI. I've been searching for at least an hour and have not found the same problem/answer.
SCENARIO
My friends and I are attempting to get an OLED and rotary encoder working together using... |
H: What are the (ill) effects of drawing too many amps through a DC power supply
I am running 256 WS2811b RGB LED "pixels" off a 5V 8A power supply. After about a week, I'm noticing the power supply runs quite hot and I'm worried I'm damaging it (or causing some other ill effects that I"m not aware of).
Since a lot of... |
H: How to repair ripped off solder pad
So the left button of my mouse was broken and I wanted to repair it by replacing the switch. But when I took the switch off the solder pad came off too. As you can see in the picture below I tore it off clean. Is there anything I can do to save and fix this?
For the record I am ... |
H: Mechanical or Solid State Switch for 48V DC and 2 Amps current
I've been looking for a SPDT switch that can support 48VDC and 2 Amps current but so far I haven't had any luck. It can be mechanical or solid state it doesn't matter. Is there such a thing?
AI: An SPDT able to support 48V potential difference and 2A c... |
H: Effect of cooling a DC power adapter with too few amps?
I have a device (PC fan) which wants 2.0 amps, and a DC adapter that supplies 1.8 amps; both 12v. As I understand it, using this adapter will cause overheating and reduced voltage.
My probably-foolish theory is that I can cool the adapter (I'm customizing a re... |
H: I2C problem on STM32F303 processor, what is happening with SDA?
I am trying to add an I2C display to my remote control drone. I can't get the display to work. I took the same code and copied it to a stm32f303k8 nucleo and got the display to work. I moved the code back to the drone and tested on the STM32F303cc p... |
H: LM317 Get Stable Output voltage at 1,25 V
I am currently trying to use the LM317 with a stable output voltage of 1,25 V.
The general formula is
$$
Vo = Vref\cdot\left(1+\frac{R2}{R1}\right) + Iadj\cdot R2
$$
I used this circuit to create the 1,25 V output voltage:
simulate this circuit – Schematic created usin... |
H: Understanding Mosfet simulation and initial conditions in Spice
Here is a simple circuit with a P mosfet. I got a strange behavior when powering a circuit, so I isolated this part to understand it.
Circuit is powered at t = 3s (I've used a pulse input voltage source to simulate it). Here is a zoom on power on :
b... |
H: how to calculate the power of the energy harvester
this is a tough question for me.looking for your guys's help.This energy harvester use DC motor to collect the energy.And an external electrical load R is connected to the generator,i got an oscilloscope to to record the curve of voltage.Then the power of output is... |
H: Find transfer function from Bode plot
This is my Bode plot
The solution manual says the function plotted is $$\frac{s^2+0.02s+1001}{s^2+2s+101)(s^2+20s+10100)}$$ What I know is the Bode plot for $$\frac{s^2+2ζω_ns+ω_n^2}{ω_n^2}$$ and the inverse of that.
I can see three peaks at ω=1 , ω=10 , ω=100.
Since the plot... |
H: Adding a variable offset to a signal
I would like to add an offset to a signal to send it on a differential ADC. But i want to be able to control the value of this offset with a PWM.
My sensor has a bandwidth of [1-100Hz] and i only have a 0-5V supply.
It works well with offset of 2.5V / 2V / 1V but for 0.512V i h... |
H: Which nRF24L001+PA+LNA should I get?
I ordered 5 nRF24L01+ chips for 2.4 GHz RF. I have not done tests with them, but doing tests with my current 433 MHz results in a low speed, few meters maximum range.
So I expect with my 2.4 GHz RF's I also will need something better.
What I would like is to built these into an ... |
H: A DC source and only a Reverse Diode
What will happen having only a DC source and a diode connected in reverse?
Will the diode or the source overheat over time or something bad might happen if you let it operate like that?
AI: You're about 1/5th the way from the center on the left of the graph. You'll get a margina... |
H: Random number generation with skewed distribution
I would like to implement a fully-digital circuit that can generate a random variable X with P(1)=p, P(0)=1-p (where, ideally, the probability p would be configurable with a programmable parameter).
An LFSR is useful for pseudo-random number generation and for getti... |
H: What is the proper way to earth aluminium profile frames?
Frames built with aluminium profiles (such as 4040) do not make good electrical contacts at joints, because of the surface oxide protective layer.
What would be a good way to properly earth these frames? On my frame sits a heater which runs on 220V. It woul... |
H: Need help finding the transconductance author of this book is referring to
I am reading a book "Practical Electronics for Inventors" and I was trying to understand the FETs, at several places the author has mentioned about the trans conductance that he has noted with gm. I did understood what transconductance(gm)is... |
H: Connecting DAC to line out and headphones
I am designing a PCB with a stereo DAC UDA1334BTS and two stereo jacks -- one for "line out" and the second one for headphones. My original plan was to connect the DAC output both directly to the "line out" jack and to an input of an amplifier TDA1308 which will be connecte... |
H: 3,8 Volt to 1 Volt via Voltage Divider
I am trying to get an analog reading from a YL-69 Soil Moisture Sensor onto my ESP8266-12F Module.
The ESP8266 12F is powered via 3 AAA 1,2 (so 3,8 Volt when fully charged) Volt Batteries.
The YL-69 Moisture Sensor and the Controller Board need min. 3,3 Volt.
The ESP8266 12F's... |
H: Do I need undervoltage protection?
I am making a small, handheld device powered by a 9V battery. I am using this regulator and the ATtiny104. My question is, do I need to protect against a low voltage battery? The minimum input for the tiny is 1.8 volts so do I need a device to shut off the power when the 9V hits a... |
H: What is the name and purpose of the following component?
I'm trying to repair a small electronic door bell.
I was wondering what is the name and purpose of the white box component ?
It seems to be just a wire with some white body around.
Is it a resistor or a fuse? My guess is that 4W22R means 4 watts 22 ohms but... |
H: Help identifying a component in glass housing (looking like a resistor) and markings "PH 41 48"
I have found an electric component and am asking what its name is.
The orange thing is smaller than the a resistor, if that helps...
Thanks all.
New Info
The characters written are:
PH
41
48
AI: PH
41
48
That ma... |
H: Which of these connections are incorrect and why?
Is there a difference in these connections and is there anything wrong on any connection? I am new to phase and neutral wiring. Kindly help me.
AI: Putting colour codes aside*.
Option 2 is correct.
Option 1 will work, but is against regulations in the US, the UK and... |
H: Which frequency to consider in SPWM for a transformer, the resulting frequency or SPWM frequency?
I am build an inverter with the EGS002 board, which has a SPWM carrier frequency of 23.4 KHz. In my mind the logic is that the transformer winding, material and size should be calculated using the carrier frequency, no... |
H: Altium full-stack pad custom shape
I an currently trying to reconstruct a PCB in Altium from the Gerber files. So far, I have been able to import the Gerbers in a PCB document.
The existing Gerbers have through-hole pads that have a special shape in the inner layers (in green here):
I am able to set the pad in ful... |
H: Does inductance in a resistor matter if it is used as a bleeder resistor?
I am designing a Marx generator and I want to place a bleeder resistor across each capacitor in every stage of the Marx gen.
I have been looking at using low cost RI80 resistors from eBay. Each stage of the Marx will be charged by a 45kV powe... |
H: Connecting an open-collector output to a transistor base using a single pull-up resistor
I have a Hall-effect sensor with an open-collector output rated for max. 25 mA. This sensor will be used to switch an NPN transistor powering a 12 V LED strip. The load is 300 mA.
Could I get away with a single pull-up resistor... |
H: Current between RC and RL parts of a circuit
I got stuck on a problem, and I've found the source of my confusion but can't figure out. Cutting to the chase: in the following circuit, the behavior when the switch on the bottom is closed makes complete sense to me, the capacitor being an open circuit and the inductor... |
H: Why does my transistor turn "partially" off?
I'm trying to get IV curves of the BFP720FESD NPN bipolar junction transistor using a PXIe-4162 SMU.
I do a sweep of 0-3V on the collector for six base currents between 5uA and 85uA and measure the collector current.
DUT schematic (please ignore the erroneous JFET symbol... |
H: Conversion of radio emissions to decibels and role of impedance ratio to power ratio
This question is about a web article about radio noise suppression by Ferrite beads.
The above diagram plots of a family of four curves for the ferrite bead. Each curve depicts the relation of impedance to frequency for some value... |
H: Finding an IC without really understanding the numbers
First of all, this is only about learning & seeing if I can revive a tablet.
I have an Onn tablet that even tho it is a few years old has only been used less then 5 hours. The battery was flat which I expected. I hooked it up to a charger and it draws .09 amps ... |
H: 2 Coil Latching Relay
I am using a 2 Coil Latching Relay and I was hoping that someone could confirm if my understanding of the relay I am using is correct. The part number I am using is a TQ2SA-24V (https://api.pim.na.industrial.panasonic.com/file_stream/main/fileversion/4514). From their datasheet, the manf state... |
H: Working on 64-point SDF FFT Verilog code
I am an undergraduate student who has chosen to work on an FPGA project for my capstone. My professor provided me with a PDF file without any context, and now I am trying to figure it out on my own. I have a Verilog code for a "64-point SDF FFT," and my task is to complete t... |
H: Why does the MOSFET Vds vs. Id graph stop at a certain point?
Why does the Vgs=15V line stop at around Vds = 3V? Is it just because the behaviour can be guessed by seeing the lower Vgs lines, or does the MOSFET not work at Vds>3?
This is from the IRFZ44N datasheet.
AI: The IRFZ44N has a maximum pulsed drain curre... |
H: How much voltage can a contactor withstand?
I tried searching, but unfortunately did not find an answer. Given a typical 24V AC (or DC) contactor, how much voltage can the contactor control circuit withstand? Will it be damaged by mains electricity?
AI: Contactors are similar to relays- they are electromechanical d... |
H: Need regulated 15 kV output
I was just playing around with this ZVS circuit I made in LTspice. It was made to output 15 kV, but when I saw its actual output it had spikes of 25 kV, then it stabilized after a while. How to prevent this misbehavior when making the actual circuit?
The circuit:
The output:
EDIT: I've... |
H: Old oscilloscope has its plastic screen slightly shifted, is it safe to use?
I found an HP 1220A oscilloscope in a thrift store.
It's in pretty good shape, but I noticed its front green/blue plastic screen is a bit shifted to the right.
I can slide it back in place with my hand? I just want to make sure this isn't ... |
H: How to make 0.1" male headers to fit into female DIP socket that has holes which are too small?
I recently received my largest batch yet of assembled PCBs. The design hasn't changed since the last order, but the supplier's stock of a socket I had been using has been depleted, so I substituted a different socket.
O... |
H: How critical is SOT89 footprint?
I've pulled datasheets for a dozen compatible NPNs from Toshiba, Diodes, Onsemi and Nexperia. They all had different recommended layouts for SOT89 package. More than that, Nexperia has different footprints for wave and reflow, KiCAD has yet another layout, and simple picture search ... |
H: Can anyone tell me what this circuit is doing?
I am reluctant to share the whole circuit due to company confidentiality, but effectively a frequency ref is inputted into Q1B. Q1a's collector is connected to 3V3 through a series of resistors and a frequency output can be measured there based on manipulating a capac... |
H: PSL usage in Formal Verification, assertion problem
I am investigating the usability of formal verification in FPGA designs using VHDL, PSL, SymbiYosys, and GHDL. I've watched several webinars, read a PSL book, and gone through tutorials. Currently, I am attempting to create test assertions, but I'm facing numerous... |
H: What is the best way to implement an accelerometer with existing Modbus equipment and limited ADC resolution?
I need to find the easiest and cheapest way to add an accelerometer to my current set up.
I only need to detect local disturbences that will affect the weighing process that I am carrying out.
My current se... |
H: Why is there a negative source voltage when the MOSFET is off in this buck converter?
This is the voltage source. As you can see, when there is a turn-off phase, I have a negative source. Why?
AI: Why is there a negative source voltage when mosfet is off?
It's an asynchronous buck converter and, when the MOSFET ... |
H: LTspice model file for new component
I would like to add some new components to the LTspice library. I have never done this before.
The online SPICE forum discusses 3rd party component steps. It says I have to download the SPICE model file from the manufacturer's website. I have tried to find the SPICE model file f... |
H: Antenna tuning and L/C matching
I see there are already a few questions asked wether it is better to physcally tune the antenna for said frequency and impedance or use a matching network. It seems the conscenus is often the physical way is prefered firstly. But id like to know exactly why. From my current understan... |
H: 4-20mA analog output into a digital input?
I'm measuring the 0-10V pressure output of a pressure sensor with a LOGO! smart relay (PLC). I would like to make sure that the pressure sensor is working even when I'm measuring nearly zero values with the device.
My idea was to connect the other output (4-20mA) of the se... |
H: My Sallen Key Butterworth high pass filter's frequency response graph is not responding
I tried to make a cutoff frequency of interface in partial discharge but the response frequency graph is not responding.
I already changed (Amplitude= & frequency= 50Hz) in the sine generator properties and DC generator propert... |
H: Detecting water (via resistance) between two metal probes using 3.3v MCU's ADC
For the past few days, I've been going in circles trying to plan a circuit to detect water between a pair of metal probes (or more precisely, between several pairs of stainless steel probes approximately 1 inch apart connected in paralle... |
H: Core demagnetisation - What is the condition?
Consider forward converter topology.
What is necessary for core to be successfully demagnetised? Does the magnetising current has to reach absolute zero amps, or even little negative is advantage?
How about voltage across windings? Seems the voltage reaching 0V naturall... |
H: Offset Voltage not matching Datasheet
I'm using the OPA4990 Op Amp from Ti for a project and I noticed today that the offset voltage seems to be larger than the datasheet specifies.
I'm using one of the op-amps as a voltage follower in the unity gain buffer configuration. I measured the voltage present at the input... |
H: OVP MOSFET Circuit
I've been trying to make a circuit that once a certain voltage (in this case around 7.1V) is supplied by the power supply, a MOSFET will disconnect the load from power. I know there are other alternative OVP circuits out there but I was curious to see if something like this would work. I haven't ... |
H: Using a BNC shorting cap as a switch
Regarding this short-circuit BNC cap:
Is there a way to know if the cap is isolated from the inner BNC pins where the current will pass through?
I want to use this as a lock with a panel mounted BNC, so that when the cap is plugged it will act like a switch for 12 V. I am not su... |
H: Reading voltage across Christmas light wires, multimeter shows erratic readings
I am attempting to splice a simple on/off switch into a strand of Christmas lights.
Previously, I separated the two wires and cut open the one marked with dots, expecting it to be the positive/live lead. I joined the two leads of the sw... |
H: Op-amp not increasing amplitude of signal
I was doing some LTSpice simulation with an op-amp to amplify a 1 millivolt 40 kHz sine wave. However, in the output signal, it had just raised the voltage of the whole waveform, it decreased the amplitude. The amplitude now was under 500 microvolts. I was expecting it to o... |
H: Zener diode on NRST pin of STM32
I am using STM32L476QGI6 in my project. As shown in the following figure, I have placed a 3.6 V Zener diode (ZM4729A-GS08) on the NRST pin of my microcontroller.
The problem is that when I connect the 3.3 V power supply to the MCU, sometimes the microcontroller turns on, and sometim... |
H: DIN rail terminal block resistor
Is there a reliable solution for placing my own through hole resistor into a DIN rail mountable terminal block? Or is there any off the shelf solution the use a resistor to convert my 4-20mA current output of my pressure sensor to 2-10V signal?
I'm using a LOGO! smart relay (PLC) wh... |
H: TRIAC controlled fan output on furnace control board not working
At board power-on, the fan output connector has mains (230V AC) voltage without the fan connected, that drops to ~2V AC with the fan connected.
At power-on, on the attached display, the board shows a message error code that means "insufficient fan spe... |
H: Can I safely remove this buzzer from a UPS PCB?
I want to remove this buzzer from this UPS PCB. It's very noisy.
For the UPS to continue working, should I just remove the buzzer with a soldering iron? or do I have to put some wire or resistance in-place?
AI: It would be harder to build the UPS so that it would stop... |
H: Can someone explain this current sink circuit for me?
I am trying to get my head around this (current sink) circuit.
I have seen this circuit with two NPN transistors and connected base - but to swap around one of them seems a little strange to me.
Does this arrangement have a special name? Can someone please expla... |
H: 230 V AC motor not running
I have a 230 V shaded pole motor of a dehumidifier that does not work anymore. The motor makes absolutely no noise when connected to 230 V. The rotor spins smoothly, there is not much dirt in it.
That motor is very simple: 4 coils, an inner magnetic shaft, and nothing else except a compon... |
H: 10MHz reference vs 1 PPS vs GPSDO
In the context of Software defined radios (SDRs), what are the differences between using an external 10MHz reference versus using a GPSDO? Why/when would you use one over the other? And how does the 1PPS relate to all this? Is the 1PPS only used for system time? What happens if you... |
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