Questions tagged [switching]

Switching can be defined as the change in state whether it be an analog, digital, or mechanical device. For digital devices, switching can be defined as a transition from HIGH to LOW or vice versa. For analog devices, switching can be defined as a change of operation within a transistor. Mechanical device examples include physical light switches or button switches. Ultimately, switching interrupts current from going into another conductor path.

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41 views

Need some help with design for reduced friction acceleration of a ferromagnetic mass through a barrel

I would like to levitate (by that I mean just enough to not make contact with the surface of the barrel) and accelerate a ferromagnetic mass along a barrel of a certain length. I have a few questions ...
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59 views

Switching voltage regulator - exceeding output voltage limits

I have been designing a digitally adjustable step-down voltage regulator. Mainly because of the availability and price I chose: MCP1612-ADJI/MS I followed the datasheet and created the following ...
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81 views

Switchable dual power inputs

My Raspberry Pi 4 project will be powered by a single official Pi power supply with a USB C plug. I want to provide power sockets on both the left and right side of the housing, but this is for ...
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61 views

How to separately charge two LiPo batteries wired in serial?

I would like a circuit where 1) two protected LiPo batteries are wired in serial to power the load; and 2) when external power is plugged in the load is disconnected and the batteries are charged ...
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2answers
68 views

MOSFET Switch in 120 Vac application with Arduino Uno

I am working on a project that requires an Arduino Uno to activate a safety mechanism using 120 Vac from a power supply. I have little experience in electronics and EE. I want to ask if the following ...
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21 views

MOSFET on-time calculation vs. measured

I'm trying to compare the measured on-time of a fet compared to the theoretical on-time of the fet. My calcs are not aligning with the measured result. Here is my approach: The fet is a NIKO-SEM ...
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60 views

What component should I use to regulate power during runtime? [closed]

I have been thinking about a way to reduce heat produced by my resistive wire based on some user input. My circuit is basically a simple resistive wire and arduino, both powerd by Li-Ion battery pack ...
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88 views

Why is my MOSFET ON when there is no gate voltage and OFF when there is a gate voltage? [closed]

I have been working on a coil gun but am having trouble with the firing mechanism. My coil gun capacitor bank supplies 400v and instantaneous current of 666 amps based on the resistance of the coil. ...
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50 views

How do you check what the highest switching frequency a PWM IC can handle?

How do you check what the maximum switching frequency a PWM can handle? Also, how do you check what the maximum switching frequency a op amp can handle? Because some datasheets don't give this ...
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36 views

What is "drive" (in units of coulomb) in this datasheet?

In the datasheet of the family of step-recovery diodes (they are essentially PIN diodes with the I layer "very thin") MMDx of MACOM (link here), following figure is given I understand that ...
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1answer
104 views

Does this circuit work to switch a load with a microcontroller?

I want to create a circuit to switch loads (e.g.: led lights). Following requirements have to be met: the load should keep it's state when the microcontroller goes to sleep/powers off the load could ...
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53 views

Problems with enabling and controlling multiple instances of magnetic pendulum coil circuit

I have some questions about a circuit I'm using for an upcoming art piece. I've been using the following circuit schematic that discharges current from a wound coil every time a magnet pendulum swings ...
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93 views

What parameters to look for in selecting D2 and Q1 for 3500 mA backup power?

Which transistor and diode is suitable for fast switching power and low discharge battery when Vin, for PWM 1.2-29 KHz, 4 A, 3.7-5 V? And which capacitor should be at the output to smooth the ...
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49 views

Headphone and speaker switching

I am having difficulty with a headphone plugged in and speaker mute configuration. I am using the SJ-3524-SMT-TR headphone jack and the TPA711DGN audio amplifier IC. What circuitry should I use with ...
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63 views

Question regarding the MOSFET gate Miller plateau region

During turn of on an N-MOSFET, the gate drive dynamic characteristics curve looks like this: The gate voltage across the gate terminal of MOSFET rises linearly for charging input capacitance Ciss ...
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2answers
86 views

Inrush current when n-channel MOSFET turns off

We are using a FDN028N20 n-channel MOSFET for load switching. Load current is 80mA max. and it is controlled via processor's 3.3V pin (NRF52832). Our schematic: When the MOSFET turns off, I measure ...
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47 views

Using an N type device as a high sided switch

The attached circuit is a battery switching device that, at regular intervals, flips a relay and so switches which of two batteries is powering a load. As an already built device, it seems to work ok ...
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36 views

Terminal AC voltage of the resonant inductor in LLC resonant converter

For this LLC resonant converter circuit, the switching frequency is calculated between 80 to 127 kHz. To select the terminal AC voltage of resonant inductor(Lr), the formula is used as below in TI, ...
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89 views

Reducing relay contact chatter from bimetallic switch control (AC coil, mains voltage)

I am looking for a few techniques to reduce contact chatter in a relay controlled by a 120 VAC voltage signal. The circuit uses a bimetallic thermal switch to turn a resistive heating element on and ...
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88 views

Switching 3.3V 150mA efficiently

I have a load (from 20 LEDs with 20 resistors) that I want to switch on/off as a single block, using a GPIO pin from a micro-controller. I have measured the current to be 145mA at 3.3V Vcc. simulate ...
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2answers
56 views

Measure battery voltage from a device that powers up/down periodically [duplicate]

I have a MCU that powers up periodically to log some data and then powers down (full power off -- not sleep). When powered on, it runs off a battery and I want to connect the battery to an analog pin ...
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47 views

Frequency based switching

I have two square waves of different frequencies (f1 and f2) and two circuits (ckt1 and ckt2). I want to design a circuit such that on the input when f1 square wave comes, ckt1 gets activated/turned ...
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36 views

Using a CDS Cell to turn a motor on or off

I want to be able to use a MOSFET switching circuit to be able to turn a motor on when a CDS Cell detects light and is off when the CDS cell is covered (for example in a dark room the motor is off). I ...
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30 views

ESP8266 deep sleep with external wakeup from 2 different GPIO

I'm trying to create a sensor that checks if the mailbox got new mail and when its emptied (it has 2 diffrent slots) Is it possible to wake up an ESP8266 and checking which of the microswitches are ...
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119 views

Switching both GND and POWER

I have multiple sensors and I need to completely isolate them from each other while working (in terms of Vcc and gnd). What's the most reliable option to completely switch gnd and Vcc (not only one of ...
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41 views

Way to handle rapidly changing current demands and excess heat

So I have a circuit like this: And I am driving it with a desktop power supply at 5A (<1 Volts varies by coil). The issue that I am having is that my power supply is overheating. I am rapidly ...
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1answer
126 views

Calculating power of induction heating of brass

I got this project to make, to anneal brass pipe edges (to be more precise, empty brass gun-shells) of diameter about 8mm. I would like to raise the temperature up to about 450-500°C in few seconds, ...
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3answers
84 views

Will there be major negative side effects to hot-switching between two mains AC sources that are not in sync?

I am currently thinking about creating a "box" with a wall outlet, solar input and mains source input. This device will use a solar panel to charge an internal lead-acid battery. It's ...
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90 views

Intrawinding capacitance in high turn transformers

There seems to be a known phenomenon about high turns ratio transformers drawing no-load current in higher voltages with higher frequencies. The intrawinding capacitance in the secondary (Cds in the ...
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959 views

How should I understand back-EMF in an inductor?

I have a circuit made of a MOSFET that pulls the lower side of an inductor to ground while the other side is connected to a DC voltage source as follows: Then it is very simple to describe what's ...
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45 views

Secondary Coil Malfunction in an SSTC Circuit

I’ve designed an SSTC circuit which is based on a different topology and I wanted to accomplish it in real life. The circuit is operating at approximately 1.5 MHz during resonance and inherently, the ...
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75 views

Synchronous DC-DC buck converter body diode switching loss

I have a couple of questions regarding the body diode of MOSFET. I was looking at the calculation of the switching losses in the synchronous buck converter. For calculating the turn-off switching ...
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57 views

P-Channel Switching Circuit

I want to use an IRF9530 MOSFET and a variable resistor to be able to switch an LED on or off depending on the value of the variable resistor. Eventually I also want to incorporate a MOSFET inverter ...
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1answer
69 views

Switching buck/step down converters with resistive lamps

I need to power a halogen lamp with a constant power (5 V 900 mA) using a constant current switching driver IC. I will not use an LDO IC, since my power supply is 24 V and it will generate too much ...
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89 views

Efficient discharge of capacitor voltage to 2-10 ohm DUT

I need to apply the voltage in a capacitor to a load (between 2 and 10 Ω) and need to have the most efficient and simple method to do so. The goal is to apply power to a DUT (device under test), ...
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49 views

UPS for WiFi router (automatic switching between battery and DC adapter )

I want to make a UPS for a WiFi router. Following is the schematic I am thinking to implement. My idea is to implement the following: The input DC adapter will provide power to the two converter ...
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2answers
74 views

IC for ultra-low power switching

I've previously used complimentary pairs (eg DMC2990UDJ) to switch ICs on and off. I've attached a schematic which switches a potential divider for battery voltage monitor as an example. Where R7 and ...
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232 views

How to generate a -12V to +12V PWM signal from 0V to 3.3V (or 5V)

I want to build my own Type 2 electric vehicle (EV) charging wallbox. In order to communicate the maximum charging amperage of my wallbox to the EV, I have to generate a -12V to +12V PWM signal of 1 ...
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1answer
94 views

Can One Flyback Diode be used for multiple relays controlled by the same switch?

I am working on a project where several 12V relays need to be controlled by the same push-button switch, essentially running the relays in parallel. I wondering whether relays configured in this way ...
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61 views

Is it true that buck converter FETs are driven from LDO?

As per the below document https://www.onsemi.com/pub/Collateral/TND388-D.PDF higher switching frequency has the drawbacks listed. Iam unable to understand Is FET driver in a buck converter internally ...
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60 views

Can hazards increase switching time and/or number of switchings?

In connection with question CMOS gate logic switching time based on input vectors one of the answers mentioned hazards. Although the question was about the switching time, finally I did not find the ...
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65 views

Half of voltage on GPIO when using external pull-up

I added a pull-up resistor to GPIO in order to use the reed switch. You can see the wiring in the picture I attached. It works but I'm confused why when I wire multimeter to PB0 and GND it shows about ...
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3answers
109 views

LM2576 ON/OFF pin for over voltage protection

I'm trying to shut down an LM2576 regulator in the event that one of its adjusting resistors fails open. I'd like to use the ON/OFF pin on the regulator as this seemed as though it should be easy and ...
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51 views

Help Understanding the Biasing Networks of High Voltage Amplifier Circuit

I found the design below in a Circuit Ideas magazine / publication from 2004. I'm a bit lost on what FETs M1, M2, M9, and M10 (Q5, Q6, Q11, and Q12 in the publication) are doing and why they are there....
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1answer
102 views

Calculated vs. Measured MOSFET Switching Times

I am currently evaluating several power MOSFET’s looking at their switch on and off times. My testing has employed a few different gate drivers, however the bulk of my testing is with the ST Micro ...
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85 views

What do you do with 5 VDC at 150 amps? [closed]

I recently picked up a switching power supply that is rated for 5 VDC at 150 A wondering in industry where you might find that being used. I was told possibly older industrial computers still running ...
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112 views

2.5 kV Low Frequency Switching Circuit

I am working on designing a circuit to generate and switch a 2.5kV and -2.5kV power supply to generate a high voltage square wave. The intent is to generate an electrostatic field between two ...
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3answers
153 views

MOSFET still turns on LED in off state

I am designing a LED flashing circuit with a MOSFET. With a 5V input signal it will drive a 2 watt LED when the 5V is switched on or off. The problem is when the MOSFET is in an off state 1.420 volts ...
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76 views

How to fix this AC switching circuit?

I am trying to replicate a small circuit of an optocoupler and a triac, see this document for details (second page / "EL Channels"): http://cdn.sparkfun.com/datasheets/Components/EL/...
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69 views

Mains safety shutoff

I have a problem. I have a sensor in a piece of equipment that needs to switch off that equipment if it detects a dangerous gas. The equipment must remain off until a manual reset is applied. What ...

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