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1 vote

capacitive filtering of power line transients without power loss

Well, without any detail of what device is in question, or applicable patents if any, there are two typical possibilities. First, consider the equivalent circuit used to test surge: simulate this ...
Tim Williams's user avatar
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1 vote

capacitive filtering of power line transients without power loss

An ideal capacitor is has only reactance and no resistance. So the ideal capacitor is only an energy storage device, rather than energy dissipative. So when considering "active power" (aka &...
BK303's user avatar
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0 votes

Can I mix 5v power sources? how about 24v power sources?

Assume first question is: Suggest a circuit to connect both a primary and a backup DC voltage supply to a load with preference to the primary? The answer depends on the voltages and reverse current ...
BK303's user avatar
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1 vote

PoE power extractions using RT9400

can I directly use RT9400 with PoE connector to extract power without using magnetic transformer? Short answer: Yes, as long as the PSE (power sourcing equipment) decides operation mode is Mode B or ...
Rohat Kılıç's user avatar
2 votes

Powering a device from the RS485 lines

RS485 has impedance about 100 ohms and signal voltage about 3 to 5V so while it's active you have about 250mW best case 100mW worst case probably enough to run a small microcontroller if you replace ...
Jasen  Слава Україні's user avatar
5 votes
Accepted

Powering a device from the RS485 lines

Where is the power coming from to power this converter? (I assume RS485 A/B) your serialcomm.com link says on the specification page, under "electrical", that it's powered from the RS232, ...
Marcus Müller's user avatar
1 vote

Powering a device from the RS485 lines

Edit: one of the devices you linked to says it is powered from RS-232 side. Which makes more sense as ther is no power available from a half duplex RS-485 bus anyway. As mentioned, most of your ...
Justme's user avatar
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0 votes

How can I design a simple dual battery e-bike protection circuit?

It looks like there are prewired kits for this now easily available. I don't think they do 3 batteries though. Do a search on your big box remote river vendor for "electric ebike dual battery kit&...
J. Gwinner's user avatar
0 votes

How to isolate RS485 (A and B) from existing transceiver? Check attached circuit diagram, is it correct?

This will be hard. You cannot know when either side has enabled transmitter and will soon transmit something on bus, you only see when something gets transmitted. Perhaps if you know about the ...
Justme's user avatar
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2 votes

How to isolate RS485 (A and B) from existing transceiver? Check attached circuit diagram, is it correct?

If I've understood your goal, you have a controller device which is half-duplex RS-485 (on the left), and a slave device, similar, on the right. The controller is not isolated, and you want it to be. ...
jonathanjo's user avatar
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0 votes

Why do MCU dev boards include multiple voltage regulators?

I can't comment on the first answer but if a moderator can turn this into a comment it might be useful there. The Adafruit Learn guide for the product does offer a reason for it. Low Power friendly! ...
KevinJWalters's user avatar
0 votes

Modification on latching power circuit

If you are a little tolerant of the 'reset' time, then just capacitively coupling the switch will work. Ensure that the C you choose * 100k will keep the FET on for long enough for the ESPP to wake up ...
jp314's user avatar
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1 vote
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How to find the power factor of a component when the combined power factor and one other power factor is known?

As you correctly surmised, you can't add the magnitudes of complex power as ChatGPT says because they're vectors, but you can add them as vectors. Please forgive my drawing skills. Edit: the ...
vir's user avatar
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0 votes
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Efficient Padding for UART to Minimize Power Consumption

Generic logic pins today are CMOS type. The MCU output will drive very close to GND/VCC, with a Thevenin equivalent resistance in the 30-70Ω range -- what range exactly depends on state (typically, ...
Tim Williams's user avatar
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-1 votes

Relation between C-rate and power of a battery

The C-rate of a battery is its power-to-energy ratio. Hence, please see below the respective C-rate of the bulk storages you enumerated: 5MW (power) 5 MWh (capacity) - 1C 5MW/10 MWh - 0.5C The C-...
Luisito Ramos's user avatar
1 vote

Efficient Padding for UART to Minimize Power Consumption

It is likely that there is no detectable difference regarding what you transmit from the UART point of view. Sending 0xFF or 0x00 has equal amount of data transitions anyway. Unless you know that your ...
Justme's user avatar
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2 votes
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Negative active power readings?

No, when they are turned off, they are not connected to the line, so you wouldn't see that. It's more likely that it occurs when a motor temporarily over-speeds (say, upon sudden removal of a load) ...
Dave Tweed's user avatar
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0 votes
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Switching the circuit ON and OFF using 50mA rated push button latching switch

A problem with some boost converter circuits, especially those without synchronous rectification, is that the output is connected to the input when the circuit is off. Your part has internal active ...
AnalogKid's user avatar
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0 votes

Switching the circuit ON and OFF using 50mA rated push button latching switch

Yes, this is a typical way one might use an enable input. 100 kΩ is a little high for a pull-down resistor, though; I'd use something more on the order of 10 kΩ unless you need to minimize quiescent ...
Hearth's user avatar
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0 votes

Overloading wirewound resistors

Two ten watt resistors, in series or parallel, can handle 20 W easily. A metering problem with high voltage might indicate that a different technology would be preferable; there are electrostatic ...
Whit3rd's user avatar
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0 votes
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Overloading wirewound resistors

Check the datasheet. A common rating on resistors is a five-second overload at some multiple of rated power (usually 5x). Satisfactory performance is usually gauged by resistance being within ...
Tim Williams's user avatar
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0 votes

Overloading wirewound resistors

You can run the resistor above its DC rating if the datasheet provides information saying you can do it. Typically, this would be a graph, a table, or a statement specifying various combinations of ...
user4574's user avatar
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1 vote

Using 5-in-1 dimmable power supply with PWM dimmer for LED strip

The datasheet shows a line-connected PWM module to the control input of the power supply; the one you have is not compatible. A bare potentiometer is probably easier and definitely cheaper than buying ...
vir's user avatar
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1 vote
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Using 5-in-1 dimmable power supply with PWM dimmer for LED strip

The first product is an AC powered dimmer (essentially a dimmer combined with a power supply), the second is a DC powered dimmer (same as the first but minus the power supply). Normally you would use ...
user1850479's user avatar
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0 votes

Overloading wirewound resistors

Resistors can generally be run briefly at a higher power than their continuous rating. However, most resistors are not specified for that type of operation, so it's not advised. Film type resistors ...
Neil_UK's user avatar
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3 votes
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What happens when you insert an inductor between Vcc and a MOSFET's drain?

I think there are a couple of big reasons why you are not able to predict the voltages present in your simulation: Maximum current through the inductor and MOSFET is ambiguous, since \$R_{DS}\$ is ...
Simon Fitch's user avatar
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0 votes

How I can calculate/estimate how many voltamperes I need for an isolation transformer?

You are to obtain the technical data from the name plate of the equipment. this will help understand the required parameters.
Matthew Ekponoido's user avatar
1 vote

Analog switch unpowered state

There are special analog switches for the very purpose. TI calls them FET bus switch. If you take a look at your MAX4737, it specifies analog voltage up to your Vcc, i.e. clamping your analog voltage ...
winny's user avatar
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2 votes
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What should I do when clearance boundaries overlap with SMD pins?

Datasheet: https://www.ti.com/lit/ds/symlink/tps62136.pdf?ts=1719417594079 The pad pitch is 0.5mm (p.42): IPC-7351 describes solder joint geometry and terms. This is identified as a flat no-lead ...
Tim Williams's user avatar
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3 votes

What happens when you insert an inductor between Vcc and a MOSFET's drain?

Assuming an ideal switch, we can analyze this with a two-phase solution. Assume initial conditions from the previous cycle (periodic steady state). While the switch is on, ...
Tim Williams's user avatar
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0 votes

What happens when you insert an inductor between Vcc and a MOSFET's drain?

You must be more careful when making schematics: - ... Or you will get confusing results. Your 2nd diagram is correct. The inductor will produce a flyback voltage when the MOSFET turns off. So, if ...
Andy aka's user avatar
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3 votes
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Recommended way of power switching external modules & peripherals

Yeah, you have to disconnect (or set to zero) all pins on the device, not just depower it (cut VCC). If it's a single point-to-point connection / bus, that's fine, add the enable/disable GPIO calls ...
Tim Williams's user avatar
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0 votes
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Why Does Current Flow Through the Neutral in a Wye Transformer Secondary?

Does the current flow back into the neutral wire in a wye transformer secondary? In an unbalanced three-phase transformer (the situation your describing) current will flow THROUGH the neutral wire. ...
MOSFET's user avatar
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Why Does Current Flow Through the Neutral in a Wye Transformer Secondary?

Yes. Only if it's balanced. There isn't any other path for the return current. The neutral carries it.
John Doty's user avatar
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0 votes

Arduino and Pololu Motor Driver Shield Undervoltage Issue When Driving Relay and Motor Pump

I found out what the problem was, despite me cutting the trace on Pin 8 of the Motor Driver Shield like the website mentioned (in order to decouple Pin 8 of the Arduino from the Shield), whenever md....
Nathan Nguyen's user avatar
2 votes

How a car inverter can diffuse 16 A 230 V if the input is a 12 V car battery?

That's the maximum current rating for the connector. It does not represent the maximum current the inverter can supply. If the datasheet states the inverter is capable of providing 500W, then the ...
Tom Carpenter's user avatar
3 votes

How do I modulate the output power of a laser diode at 1 kHz?

I've taken this graph from the specification sheet linked to on this page and added the green box: - The green box represents where the laser actually produces a laser light output. Point to note: ...
Andy aka's user avatar
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2 votes

How do I modulate the output power of a laser diode at 1 kHz?

You should drive the diode with a variable current source circuit. The laser has a monitor diode mounted to the back side of the emitter in order to monitor output power. You can connect the monitor ...
John D's user avatar
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1 vote
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How to determine the correct direction of the transformer winding (photo)

Your primary winding is connected to your circuit via wires (it seems) so, once you have decided where your secondary winding wires terminate, you can do a little test with a signal generator and an ...
Andy aka's user avatar
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0 votes

Yokogawa WT3000 don't boot

From the information in the question it isn't clear what the failure mechanism is, but for general debugging suggestions about checking if the Altera EP1C3T144C8N FPGA configuration is valid: Check ...
Chester Gillon's user avatar
0 votes

Why in a inverter DC to AC 12V et 220V when I increase the voltage, the current decrease to keep the same power?

A transformer or DC->AC inverter passes Power, not just Voltage or just Current. Power is Voltage times Current, so if the transformer or inverter increases the voltage, it must also decrease the ...
Peter Bennett's user avatar
0 votes

Why in a inverter DC to AC 12V et 220V when I increase the voltage, the current decrease to keep the same power?

Amps (A) is voltage (V) divided by resistance (R): A = V/R. Correct - for a resistor. I have a step up inverter that steps up voltage... So it would be logical that more voltage pass on the out side ...
Transistor's user avatar
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1 vote

Why in a inverter DC to AC 12V et 220V when I increase the voltage, the current decrease to keep the same power?

Unlike simple passive loads, an inverter uses active electronics to switch connections on and off as needed to provide its designed output. When the input voltage is higher, these connections don't ...
Hearth's user avatar
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0 votes

Which one will turn the ceiling fan faster? Current, voltage, or power?

There is a connection between current and voltage. Thus, you can not feed 1 volt and make it draw 5 amps. This depend on the resistance of the motor. If you feed it 5 volt and it draw 1 amp, then the ...
Klaus Nielsen's user avatar
3 votes

Which one will turn the ceiling fan faster? Current, voltage, or power?

For a given fan, you only have one degree of freedom: if you set a voltage, then there is only a single possible current (and a single possible power). And if you set a current, then there is a single ...
Sandro's user avatar
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3 votes
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Calculating junction-to-ambient temperature rise for switching MOSFET

Temperature rise is what happens after heat has conducted through the materials the MOSFET (die and package) is constructed from, what it's mounted on, and any heat sinking or convection flow along ...
Tim Williams's user avatar
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3 votes

Calculating junction-to-ambient temperature rise for switching MOSFET

In your case, use the steady-state rating. The transient rating would be, for instance, if you were building in brief overcurrent capacity on a marginal thermal design. Please take notice of the notes....
vir's user avatar
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0 votes

Maximum Power Transfer Theorem Question

Electricity distribution authorities around the world disregard the Jacobi theorem because they seek maximum efficiency, not maximum power. The maximum efficiency if you use the Jacobi theorem is 50%; ...
Brian's user avatar
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1 vote
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Which component is likely raising the temperature measurement on my BME680 sensor board?

R1, R2 and R7 appear to have some logic voltage across them and they are very low value so they would be my first suspicion. I don't see any reason offhand why they could not be 100kΩ or even 1MΩ. For ...
Spehro Pefhany's user avatar
0 votes

Can Thunderbolt be used to power the host device?

With thunderbolt over USB C (thunderbolt 3 and newer) the answer is very much yes. The negotiation protocol can negotiate a thunderbolt data connection, with the laptop as host, while simultaneously ...
Peter Green's user avatar
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