New answers tagged switches
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Somewhere around 25 AT will be more than enough to prevent accidental triggering from the earth's field, although you could go higher depending on your magnet and the proximity to the switch.
The trick is to get the alignment right. You want to align the magnet and reed switch so that the reed switch is magnetized along its length. See https://...
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https://www.digikey.com/product-detail/en/te-connectivity-alcoswitch-switches/FSM2JELGEATR/450-2153-2-ND/2400357
My guess is its a TE connectivity part, maybe one like the one shown above.
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The orthodox way would be via transfer function/Laplace transformation. Just a few hints:
U_c(s) = E(s)*Z(s) / (Z(s) + R_2).
E(s) is the transformed step function, Z is the parallel complex resistance of C and R2, s is the complex frequency.
The step function's Laplace Transformation is 1/s.
.
(Some easy algebraic calculation in the frequency domain)
...
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The Problem(s)
There are several issues with your CD4011-based design.
Digital chips do not have a well-defined switching thresholds. VIH and VIL set upper and lower limits, but the actual switching threshold varies, and is usually somewhere in between.
CMOS logic chips do not like slow-transitioning signals. They tend to draw excessive amounts of power ...
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As you noted, you have a logic flaw where several of your if statements might be true simultaneously. This should be solved with the equivalent of switch, namely if() else if() .... This is the least of the problems though.
The root of your problems seems to be the lack of "debouncing", which is mandatory for all forms of buttons and switches. This is ...
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What about a voltage divider like the attached schematic?
It is only 0.5 mA plus 3 mA at the base of the BC337 transistor.
That way you don't need any zener diode, do you?
(Forget about MPPT on the diagram below, I am trying to control an old non-configurable inverter with the output of a new configurable MPPT.)
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Either SPDT or DPDT switch will work. As long as you break the loop connection between the batteries it's ok if one terminal is connected. Current only flows if you have two or more connections.
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That sounds good, electricitly needs a circuit to flow, putting a switch in one wire is sufficient to stop the flow.
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This is one of the possible solutions to my question, which is based on Peter Smith's comment. I replaced the AND assignments in the IF statement condition with a Boolean equal to operator.
Below is the corrected code which is now working and functions how I described it should in the question:
#include "include/tm4c123gh6pm.h"
#define RED_LED (1U << ...
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Here is my summary (I can expand on some details, if needed - I don't know how many quotes from the datasheet etc. you want):
I would not use this device for driving a logic device; it's specifically designed for driving high-power loads in automotive applications, and as such, it has special features you don't need including "open load detection".
The ...
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The FET body diode has the Anode on Source which on the OA output causes Vout max = 0.7V while the OA inputs are at 0V in the linear mode of operation.
Your design show T= 1ms with R=1k, C=1uF. You have not given any design specs for integration time and discharge time.
A more practical solution might use a Transmission gate or bipolar Analog Switch with ...
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Reset Switch
You should not use discrete MOSFETs for this due to the body diode. A single SPST analog switch such as the DG417 or DG9421 would be ideal for this task. These devices have a logic-level threshold and can operate over a wide voltage range due to the fact that they utilize a transmission gate.
Just one caution: you will probably want to place a ...
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Although it is often not shown in the MOSFET symbol, they all have a diode between source and drain. This is called the body diode.
If the source goes more positive than the drain by more than a little bit, the MOSFET will conduct regardless of gate voltage.
You might be able to solve this by adding a second MOSFET in series with the source and drain ...
1
I'm sure Bruce Abbott's answer is a good one, but just as an alternative approach - and a more general answer to how do I switch something based on an LED's current - you could use an optoisolator:
simulate this circuit – Schematic created using CircuitLab
I've disconnected the blue LED from the circuit and replaced it with the optoisolator LED. I'...
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I suspect the LED circuit looks something like this (resistor values are a guess):-
simulate this circuit – Schematic created using CircuitLab
You don't see 0V on either LED leg when on due to the current-limiting resistors, and you don't see 3.3V when off because LEDs drop some voltage even at the very low current your multimeter draws through them. ...
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One difference that could be significant is that in Fig 2 the discharge current flows through the power supply, increasing total energy draw but also slowing down the supply current change.
If the coil is switched on and off often then Fig 2 could double the power consumption. This is not a good solution when using PWM.
On the other hand, the diode in ...
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The length of time that the current in the inductor takes to drop to zero can be reduced be placing either a resistor or a Zener in series with the usually seen freewheel diode.
The usually seen freewheel diode is still required because it stops conduction through the resistor or forward biased Zener when the transistor is on.
The resistor's value would be ...
1
It depends on what the coil is for and what you want it to do. For relays, a 100 ohm resistor is often placed across the coil to dampen the energy yet permits the relay to open/close quickly. If the coil is part of an actuator and the coil is pulse width modulated, then a diode is placed across it like you have shown. If you connect the zener to ground ...
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It's frequently used in applications such as actuation of fuel injection solenoids where it's important to collapse the magnetic field as fast as possible.
Edit: See, for example, the LM1949 fuel injector driver IC which shows an external 33V 5W zener diode. Typical 'on' timing is 2.5 to 3.5ms, and a typical inductance is in the ~2mH range.
It's also ...
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Compared to (1) where the diode conducts in the forward direction, the zener diode in (2) breaks down in reverse to present a larger voltage drop to the inductor which it act as a power source when it kicks. This drains energy from the magnetic field more rapidly and therefore collapses it more quickly.
My understanding is this helps solenoids reset faster (...
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I have a box and I want to have LEDs glow when it is opened
I can think of several options...
A switch designed to light the inside of a cupboard when the door is opened. Available at home improvement stores, online, etc. Keywords: Door light switch. Caveat: make sure the switch closes when the door opens!
Magnetic switches for alarm systems. Beware: ...
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You just have to buy a NC-switch. There are a lot of these devices.
If you don't want to change the type of the switch (I'm assuming you have some sort of NO-switch), you can flip the switch around, add a spring which keeps the NO-switch in the closed position and add some sort of a lever which acts against the spring. The lever then can be moved by closing ...
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The last solution you have linked can work as expected for your application. I simply ran it through falstad with normal XOR gate and it works as expected. But XOR gate with Schmidt trigger input is highly recommended.
When the toggle switch is flipped from off to on AND from on to off,
allow a momentary connection across the keyboard contacts
Any ...
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Ran across this same issue recently, a voltmeter will not provide enough load on pin 3 output to turn off(floats at 10v) with a low on pin 2. Connect a 10k resistor from pin 3(load)to ground while monitoring this with your voltmeter send a logic high to pin 2 then a low to pin 2 and you will see that the output will turn on and off as it should.
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How is your ESP8266 powered? Via the sensor? How far is the sensor from the ESP8266? How is the sensor powered?
It is not a good practice to power the micro controller through the sensor.
A good approach to this is to put your ESP8266 into "power saving mode" and let the signal from the sensor "wake-up" the ESP8266 via interrupts. this video explains on ...
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You may also want to look into the FX101L from Island Labs.
https://islandlabs.eu/cml-fx101.html
It looks to be very a very similar part to what you are attempting to replace.
Picture Source: See above link.
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If I was tasked with the design requirement to come up with a replacement for the FX301L I would be looking to make a small daughter board that could be retrofitted into the location that the old part was mounted. There are some mixed signal ICs available that include a microcontroller that could be deployed to make the daughter board.
I would take a look ...
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