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5

You're mixing up some things. The flyback diode is needed at the relay's coil because of the coil's inductuctive behavior and the fact that the current through the coil is switched of instantly (not gradually) and the fact that a transistor is used to do that on/off switching. Transistors are sensitive to overvoltage. Such an overvoltage can occur ...


3

Preferably all your GNDs should be connected at one point and one point only. Near to your power supply is best. You don't need to connect them to the chassis. If you wanted your DC- to match your Earth, you should connect it at the power supply to the Earth wire. Doing so can help with noise, but it means your DC side is no longer isolated.


2

It is certainly possible. The size of capacitor needed would likely be in the super-capacitor class, with a capacitance over 1 F. However, you would now need to adapt your power electronics to handle this new load. When the super-cap is discharged it almost looks like a short-circuit from the perspective of a low power linear regulator. It would be much ...


2

If I do understand your question correctly, I think you can just use one relay, but "the other way around" (instead of 1 output serving 2 outputs, using it as 2 inputs serving 1 output): simulate this circuit – Schematic created using CircuitLab


1

Your best solution may be to use an opto-isolated Triac driver to drive the power Triac and achieve ON off control with galvanic isolation and low EMI from the built in zero-crossing switch (ZCS). Since the slew rate of temperature is slow, no DC controlled pulse is required. It will cycle on and off and regulate to whatever set point you choose with an ...


1

Zin = (RL)^2/Z0 No, that is incorrect. When you have a quarter wave transformer the \$\tan(\beta\ell)\$ part goes to infinity hence the formula for input impedance becomes: - $$Z_{IN} = Z_0\cdot\dfrac{Z_0}{R_L}$$ or $$Z_{IN} = Z_0^2\dfrac{1}{R_L}$$ Hence an open circuit terminating the line at the load end produces a short at the input end and, a short ...


1

An "easy enough" method is to on/off PWM the supply to the motor with a variable duty cycle square wave. . The 2SD2390 transistors are Darlingtons rated at 10A each. So use say 4 in parallel. Apply variable duty cycle square wave drive to the bases. You'll need a flyback diode/ diodes. A bunch of 1N400x (1A low frequency diodes) may be the cheapest / ...


1

I need to build a 4-20ma to 1-5v converter circuit. That's easy; it's the 250 ohm resistor shown in your top circuit. Now I need to implement some protection features like reverse polarity protection. Make the resistor a 3 watt type and it will take the full 24 volts forwards or backwards without being destroyed. You have to ensure that any circuit ...


1

The two curves are essentially the same with the second showing more detail. The first curve shows only the characteristic with no gate current. The second curve shows the characteristic with no gate current and also the characteristic with insufficient gate current for efficient turn-on (Ig > 0 and the gate current required for efficient turn-on (Ig >> 0). ...


1

If you search the Web for this issue you will find LOTS of people that have tried everything to get rid of the "under voltage" indicator. The problem seems to often be the power supply or the cable being used. In your case it sounds like you have tried everything! This is not a fix of your problem, but it is a way to get rid of the under voltage warning. ...


1

Since it is a nice sine, you can also find the delay between V(in) and V(out) (assuming V(out) lags wrt V(in) by triggering on their zero-crossings, using: .meas TRAN delay_info TRIG V(vin)=0 RISE=1 TARG V(vout)=0 RISE=1 EDIT Or even better, is there a way to get the time (and use it a variable, of course) where the measure occurs on the .measure spice ...


1

If you need to measure the Y-axis at a specific time point then, for your case, you would use this: .meas tving find V(vin) at <time_value> Similarly fot the delayed voltage. Don't forget that the measurement is directly related to the resolution of the data points. By default, it's 300 points, which can give inaccurate readings. To disable waveform ...


1

In any control system with an integrated function, such as a pulsed voltage thru an inductor and resulting current integrated to an output voltage makes is very sensitive to overshoot and settling time with say 25% step loads over the whole range of rated current. The result is a change in loop gain which makes the PID servo voltage with a single feedback ...


1

Ratings are presented in various ways. For the data sheet linked in the question, use the curves shown below to determine the allowable switching current for DC. For a 24-volt inductive load, the maximum current is something less than 0.2 amps. The Contact Ratings curves seem to show the continuous current carrying current. for resistive and inductive loads....


1

How do you know what the inrush current rating is of that relay for 24Vdc? It doesn't have one - its contacts are rated for a maximum of 6 amps RMS or 6 amps DC: - Additionally, when driving an inductive load (such as a motor) it has a rating of only 2 amps.


1

Look into a multiwinding flyback converter. That is likely to be least cost option. You should further consider isolation voltage requirements, isolation capacitance requirement, and required power ratings also.


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