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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Switching between outputs using irfz44n mosfet

In the circuit shown, the input voltage to the op-amp ua741 is 1V and the output will be 5.7V, which switches the bottom left irfz44n mosfet on and the off voltage irfz44n mosfet off. So i would ...
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54 views

Integrated circuit which acts as a switch

I have the following problem. I have an electronic door lock with opens the door whenever it is feeded with 12v (tested and it works perfectly). My main issue is that the signal for opening the door ...
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55 views

Problem with mosfet driver circuit/switching

I have the following driver circuit used for switching very high current n-channel mosfets Here's their datasheet https://www.littelfuse.com/~/media/electronics/datasheets/discrete_mosfets/...
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96 views

A device used to logically turn on a circuit with voltage being the input parameter

I’m working on a project which utilizes a power-source which is liable to vary. I have a micro-controller sitting at the output of an LDO (Low Dropout Regulator). I’m concerned about the LDO ...
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21 views

Small switching regulator EMI

Well, it's taken me weeks to think of a new absurd question but here I am at last. You're welcome! I'm looking at using a small, adjustable, switching buck regulator (likely a LM2574) for a very ...
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48 views

Transistor Biasing of high side switching network for PWM control

simulate this circuit – Schematic created using CircuitLab iagramI am attempting to create a high side switching circuit for a string of LEDs wired in parallel. There are multiple strings, all ...
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2k views

Why is my power MOSFET heating up when on?

I'm switching a 12V 500mA resistive load (LED strip) with a IRF540 MOSFET and it's getting very hot when it's on and conducting. This confuses me as MOSFETs are ...
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40 views

What is the meaning of “Sine wave energy per pulse” when referring to thyristors?

I am looking at the datasheet of a Westcode thyristor (specifically, the R3968), and it has the following graph: I am wondering if someone can explain to me what the graph is showing me! I don't ...
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For a stack of thyristors, is the “critical rate of rise of off-state voltage” scalable with the number of thyristors?

For example, in a datasheet I am looking at, the critical rate of rise of off-state voltage is given as $$2000V/{\mu s}.$$ If I have, say, five of these thyristors in series, would the total critical ...
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64 views

If an inductor is in series with each of the upper and lower MOSFETs of a half-bridge, will the switches experience zero current turn on?

simulate this circuit – Schematic created using CircuitLab I am imagining of a half-bridge converter feeding a normal resistive load. In series with each of its switches is an inductor. ...
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39 views

SPST RF switching application with PIN diode

I need a single-pole single throw (SPST) RF switch. I have implemented the following circuit for 2.4 GHz, (PIN diodes in RF switch applications / Infineon) I obtained the following S11 results with ...
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31 views

Voltage comparison circuit (Voltage level operated switch)

I am trying to implement a voltage level detection circuit for e.g. I have 60V power supply and I need to check that if the input voltage is 1.5V or higher to turn on DC/DC or just high signal so I ...
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Issue on charging current while switching two power sources

The circuit is to switch the voltage for battery charging circuit and not allow the solar power to 'other load' circuitry. The charge current is set to 1A where in this configuration it draws only ...
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1answer
59 views

Circuit to switch negative to negative, or positive to positive connection

I am wondering if there is a negative to negative (and/or positive to positive) switch. I know mechanical relays work, but I need an electronic way of doing it. Is there a transistor that functions ...
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1answer
72 views

Is Inductive Kickback Protection not necessary for AC?

For DC inductive loads, typically a flyback diode is placed over the motor so that when the current changes instantaneously it doesn't have a chance to build upon the switch contact and then create a ...
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54 views

Turn on a device if voltage drops below a configurable level?

Consider a Li-Po battery that has to be protected from damage by going below 3V. What would be the easiest, lightest, smallest ways to e.g. turn on a warning LED or buzzer (using the same battery ...
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Ribbon Cable Cross Talk - Is there a fix after the fact?

I'm involved in a project where the customer defined pins in a ribbon cable, without considering possible cross-talk issues. The signals are 1 MHz data signals with no ground wire separating them. I'...
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Switching circuit transistor NPN, load has voltage and current though transistor is off

I am confused about the switching of this circuit. I can control the V1 input line. Output line is R4 load line. My Vbase (V1) is 0V, and Vbe is 0V. Transistor is off and collector should see 0V. That ...
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73 views

On-the-fly routing of digital and analog signals using unbuffered analog crosspoint arrays?

The issue I have is strongly related to a question which was asked over here. Unfortunately I did not find the answer I was looking for. Digging a bit more I've came across a class of IC's named ...
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71 views

Triac Switching circuit with Optocoupler

I am trying to control home devices using a microcontroller and a TRIAC. For switching, I intend to use an optocoupler and triac-based circuit. The circuit is given below (also plenty are available on ...
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76 views

Why does my non latching relay design not switch back to original state as I expect?

I am using the EE2-12NUL relay and the LL4148 flyback diode. I am controlling the relay with a GPIO pin from an MCU connect to some mosfets. The coil current is 11.7mA for this relay. When not ...
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What test points to do for a switching system measurements?

I am working on a high-performance switching system. I the old ones there was no big issue in just touching a gate with an oscilloscope probe, but this time I have high voltage and very short (5nsec) ...
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30 views

What do relay switching characteristics mean?

I am looking for HV realys (3kV) and found a supplier for that. Now they offer relays with different switching characteristics: "No Load" "Make & Break" "Make only" "Carry only" On the web page ...
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IRF3205 switching problem

I bought a power mosfet(IRF3205) and tried to switch but mosfet is not behaving as I expected when gate pin is triggered it doesnt change its position. Below is how my schematic looks like, I could ...
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(Very Basic) Confused on Reading a Datasheet and Calculating Inductor Ripple Current for a switching Regulator

I am using this component for a project, however, when reading the datasheet I have just become confused about a couple of things. Datasheet : http://www.ti.com/lit/ds/slvs569f/slvs569f.pdf I am ...
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112 views

MOSFET switching with 5V but latching ON with 12V

I am having an issue with a control signal. I have a CEP50P03 P channel trench MOSFET that is supposed to switch a 12v power supply. I am having an issue I can not figure out. When I power the ...
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1answer
44 views

3 way selector switch to Push Button switch

I have 3 way video switcher which uses selector switch, is it possible to change this to momentary push button? Project - I want watch 3 video feed from camera over 1 screen, with this selector ...
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30 views

how to fix output voltage of an NMOS switch with changing load characteristic?

In an NMOS low side switch the output voltage at drain depends on the operating point decided from the Id-Vds curve and load line. According to my understanding, for a low side switch with Vds ...
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104 views

Push button to only turn off circuit

First off I have no background in electronics but have been coding since decades and have successfully built things around an STM32 blue pill. Now I am trying to build a battery powered circuit which ...
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1answer
145 views

500v generation with 24V, request for current limitation

I am generating 500V from a 24V source. Attaching schematics. This circuit is generating stable 500V. I am attaching a load of 7 kohm. In the schematics the buck regulator is supplying 19V to the ...
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1answer
168 views

Is it possible to use a NPN BJT as switch, from single power source?

I'm attempting to build the following circuit to better understand how to use a NPN BJT as a switch. What I've Tried I'm calculating the current across the LED (in order to light it up) as: ...
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64 views

Connecting an IC to LEDs - would I use a transistor?

I have this breadboard circuit, which is basically a 65C02 CPU that has 16 Address pins. I want to wire these up to LEDs. Below, I've connected them directly, which is likely all kinds of bad (Too ...
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30 views

Power button behaving as OFF-(ON) momentary switch rather than latching- Troubleshooting

I have a device which doesn't turn on normally when you press the power button like it did before. You have to keep holding it down for it to remain on. As soon as you let go, it turns back off. In ...
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110 views

PCB GND Guard ring

In my design I am using the step-up converter TLV61046a. As this is the switching device, I would like to maximize EMI reduction. I would like to hear your advice if this GND guard ring in my layout ...
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78 views

12 V pulses with 100 MHz repetition rate

I have to control an high impedance load (> 25 MΩ) with 12 V pulses with maximum 5 ns of width and a repetition rate of 100 MHz. I can generate the pulses with the required shape using an FPGA ...
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1answer
85 views

Serial line switching through a transistor

I want to switch my RS-232 TX pin.For this I am using NPN transistor in between the TX line in such a way that the collector terminal is connected to controller side and Emitter to external side. ...
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1answer
130 views

Simplest way to switch inductive load with arduino?

I'm trying to switch (just on/off) a 3.7V motor (coil resistance 2.2 Ohm) and a 6V motor (coil resistance 8 Ohm) with an arduino mini. And I have trouble finding an universal way to do so. What I ...
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58 views

Problem with stacked power mosfet simulation

I'm trying to build a Circuit Lab simulation of a stacked power mosfet pulser as described in this paper. The simulation runs for 10 ms. After 5ms, the switch flips and the voltage at 'StageOne' drops ...
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117 views

UVLO for Energy Harvester circuit

A good background on the problem can be found in the document: (Under Voltage Lock-Out Design Rules for Proper Start-Up of Energy Autonomous Systems Powered by Supercapacitors). The above document ...
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4answers
90 views

Will switching a LED on and off at a said frequency reduce or increase heat loss?

In my case, a 50W 34V LED is being used to light a small box. To reduce heat generated by the LED, we are switching it on and off at 50Hz. But I was wondering will this actually help? In the case of ...
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1answer
50 views

Fast switching with RTL inverter

I have for some days worked with an RTL inverter and an totem pole drive to drive a high voltage MOSFET. And I am happy with the result except for one thing the rise time on the inverter output (from ...
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92 views

Fixing conmutation for high voltage switching with power MOSFET

I have an issue with a charge circuit for a capacitor as load. I want to switch approximately 400 V DC to charge a 1000 µF 600 V capacitor. I'm using a power MOSFET for this application. I need it to ...
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29 views

Switching between two connections - adding LEDs to car reversing light circuit

I am doing a DIY project on my car and need some help. I have 2 LED COB on the back of the car, which is to be used for 2 different things: If I put the car into reverse gear, then the LED comes on ...
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1answer
45 views

NPN Transistor Switching 12V - grounds with different potential

I'm struggling with a NPN transistor switching problem, and in the process I've burned out a board elsewhere in my machine. Electronics is not my strong suit. I want to use a 5V signal to switch 12V. ...
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91 views

Finding R, C and Switching Frequency [closed]

I need to find R,C and switching frequency of the following circuit such that Switching Frequency is low as possible with given Vu and VL. Also how can I improve the circuit so that it can reach it'...
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98 views

How to determine maximum switching frequency of power modules?

Power IGBT and MOSFET modules give some datasheet values that look like they could be used to calculate a maximum frequency, but I'm not sure how to interpret them to do so. The datasheets generally ...
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1answer
42 views

Using P-MOSFET with Gate and Source have same voltage to protect reverse current

I have a question when I am working on MP2639A 2-cell LIPO charger (+8V4) from USB +5V. The recommend schematic uses P-MOSFET to protect reverse current from Load back to a USB plug. taken from ...
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3answers
94 views

Inductance value of an Isolation Transformer

There is a small isolation transformer 'L1' of 1:1 ratio as shown in the image. A 0-24V, 75kHz square wave is applied from push-pull mosfets stage at the 'V_SW' input of the circuit. I want to find ...
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1answer
34 views

Sharing a HD44870 display between multiple controllers

I have an existing third party system that has a HD44870 compatible display used for output. This third party system cannot be changed (for a variety of reasons), and I need to retrofit a device to ...
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113 views

Snubber for Relay Contact Switching Resistive Load

I am working on a redesign of some circuit boards and am looking for a way to save space and potentially switch to surface mount parts. Some of the largest through hole parts in use are for an RC ...