10 votes

What is an inline power switch controlled by GPIO called

As I understand what you want at the end is to have control from ESP board and being able to override it manually. If you need to override the relay in its OFF position (to maually switch the pump ON ...
7 votes

Switch that is rated for 24 V and 4 A: can it endure 8 A if I limit the voltage?

A switch that's rated for 24V and 4A means that it is designed to have 24V across it when it is open, and 4A going through it when it is closed. Neither of these figures should be exceeded. The whole ...
  • 41.6k
5 votes

What is an inline power switch controlled by GPIO called

Basically a switch that can be controlled by GPIO is a relay. relays that include manual controls do exist but these are typically going to be pulse (latching) relays because otherwise there would be ...
  • 29.8k
4 votes
Accepted

Is this caused by inductive kickback?

Can a small AC 220v bathroom fan generate inductive kickback (I thought that's DC only). Any conventional motor (whether AC or DC) will generate a back-emf when the supply is suddenly disconnected. ...
  • 414k
3 votes
Accepted

High-side switching: Load switch IC vs P-channel MOSFET

The switch will be on the high side, so I've been thinking of using a load switch IC or a P-channel MOSFET. In general, which solution is preferred when we want to minimize quiescent and leakage ...
2 votes

Does a small 8PST switch exist?

While gigabit ethernet uses all 4 pairs for data, it still only uses two pairs for power in the most common PoE standards (PoE and PoE+). PoE++ is where you need to use all four pairs for the ...
2 votes
Accepted

Celestron logic drive precision DC motor drive

The only place you can connect the power to the voltmeter so that is turned on and off by the switch is here: Looking at the back of the circuit board, that would be here:
  • 65k
2 votes

Switch that is rated for 24 V and 4 A: can it endure 8 A if I limit the voltage?

Often, switch current ratings are based on heating of the switch. For example let's say you run the switch at 4 amps and it rises from 25 C initially to 50 C steady state. And you decide that is ...
  • 28.6k
2 votes

How does a pull-resistor produce the low signal?

First, some background info... The GPIO pin in input mode will draw or source a small leakage current, typically specified as the input current, II. It's a characteristic to be aware of and to take ...
  • 21k
1 vote

Switch that is rated for 24 V and 4 A: can it endure 8 A if I limit the voltage?

I don't know if this applies here but another consideration is the break current. If an unsafe condition is caused by failure to open the contacts... well, that's not good. Sometimes it's a little ...
1 vote

How to guess the particular solution form from forcing function?

The form of the particular soluton that you propose: $$v_p(t) = \small At\sin(t) + Bt \sin(t) + C \sin(t) + D \cos(t)$$ should be:$$v_p(t) = \small At\sin(t) + Bt \cos(t) + C \sin(t) + D \cos(t)$$ ...
  • 6,460
1 vote
Accepted

How to guess the particular solution form from forcing function?

The reason is the little \$t\$ that sits in front of the sine function there. First set up the equation in standard form: $$\frac{\text{d}}{\text{d}t} v_t+\frac12 v_t=2.5 t\sin t$$ This can also be ...
1 vote

Can I use a TRIAC as an AC switch and an LDR as a switch controller to turn on and off a LED bulb?

Yes, it can be done. You can check for these two things online: Triac circuit interface with a microcontroller. LDR circuit to generate logic HIGH and LOW. Once you have these figured out, you can ...
  • 7,666
1 vote

How does a pull-resistor produce the low signal?

A practical answer to your question is that the input impedance of the MCU pin is so high it can be thought to be infinite, so it can be thought that no current flows in or out of the MCU input pin, ...
  • 109k
1 vote

How does a pull-resistor produce the low signal?

"Ideal" GPIO When programmed as an input, GPIO has extremely high input resistance (open circuit). Open switch I understand how when the switch is open, the current must flow from VCC to ...

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