12
votes
Is it safe to solder 230V wire on relay?
I do not recommend this practice, but of course I've done it a dozen times. Not for production designs, just for personal projects, or quick fixes to my own equipment. I've never had issues because I ...
- 47.1k
10
votes
Accepted
Reducing circuit to only using one transistor to turn on relay and LED
Why not try connecting the LED like this: -
I've taken you first schematic and added a wire in red.
- 473k
8
votes
Accepted
Is the use of an optocoupler necessary for a relay circuit?
Given the circuit as you have drawn it (the input ground is the same as the power ground), then, no, optoisolators are unnecessary. (Indeed they waste a bit of power.) You could connect R1 directly to ...
- 25.5k
7
votes
ESP32 Freezing Due to Contactor Noise
I looked over your "layout" artwork with a sight toward the GND plane. The colored image below is showing just how patchwork the GND fill is with each color depicting what I can best judge ...
- 57.9k
4
votes
Is the use of an optocoupler necessary for a relay circuit?
In much the same way that the relay isolates the output circuit from the control circuit, the opto is there to isolate the input circuit from the control circuit. Thus, in your schematic, you could ...
- 23.2k
4
votes
Is it safe to solder 230V wire on relay?
While the solder joints should be covered with shrink tube for sure, shrink tube alone sounds like somewhat questionable protection. Especially since this relay is actually intended to be used for ...
- 22.2k
4
votes
ESP32 Freezing Due to Contactor Noise
This is a common electromagnetic interference problem. The contactor current loop with inductance radiates broadband noise which easily is picked up by exposed wires connected to the ESP32.
...
- 148k
3
votes
Reducing circuit to only using one transistor to turn on relay and LED
In the second schematic in the question, when the MOSFETs are off, current will flow through the relay coil and light the LED. When the MOSFET is on, the LED will be shorted. So the LED will be ...
- 81.6k
3
votes
Reducing circuit to only using one transistor to turn on relay and LED
It will/might** work, but the polarity is now reversed : the LED will now be on when the relay is off, and off when the relay is on.
If D1 is high, then M1 will act as an short circuit, so the node ...
- 8,118
3
votes
What is the purpose of the relay and transistor in this circuit?
Goodness, that schematic is a shambolic hot mess. Vcc and GND are reversed on the OLED vs. ESP32.
I suppose the 7805 is supposed to reduce 9V to 5V and the ESP32 module provides the 3.3V as an output.
...
3
votes
What is the purpose of the relay and transistor in this circuit?
At the very least I think the relay is drawn backwards. It should be mirrored horizontally.
The purpose of the transistor is to provide higher current for the D23 signal from the ESP32 to drive the ...
- 206
3
votes
Accepted
Which relay is required for this time switch?
The schematic specifies that the relay contacts should be normally closed (NC), which is not something you will find easily in a 4-pin design. The reason is that 4-pin relays use two pins for the coil,...
- 47.1k
2
votes
How can I determine the type of a flyback diode that is not marked?
The JZC-42F relay coil is DC voltage, from 5 to 48 VDC, so polarity needs to be check.
Probably these relays are used to switch loudspeakers, and one point of all the coils are joined to + 24 V or to ...
- 1,787
2
votes
Is it safe to solder 230V wire on relay?
How to design without design specs!
Requirement: grid voltage soldering techniques for safety.
Satisfied: with tinned contacts before soldering and heatshrink for HiV insulation. It should be a ...
- 148k
2
votes
Dual control of relay
Here's an example of a circuit that should work with a 5V relay, easily up to 100mA coil current:
simulate this circuit – Schematic created using CircuitLab
Schottky diodes D1 and D2 form an &...
2
votes
What protection is most suitable for a relay circuit with an unspecified load (DC coil, AC load)?
For the coil side, the single diode for catching the back-EMF is usually the simplest and worst possible method, as the coil current is only dissipated by the diode forward voltage, so the current and ...
- 172k
2
votes
ESP32 Freezing Due to Contactor Noise
If the conctator is passing DC, and the load can tolerate slow rise and fall times in its power, you could add a capacitor in parallel with the contacts.
You can also add a capacitor in parallel with ...
- 27.8k
1
vote
Is it safe to solder 230V wire on relay?
I would start by choosing a relay the provides the necessary spacing between the coli pins and the switch contact pins,
Then I would solder it to a circuit board then then solder wire terminals to the ...
- 36.4k
1
vote
Can I use the same relay to switch 220V and detect 24V connection?
No, not remaining within the relay's specifications.
Switching DC is much harsher on a relay than switching AC, because arcs that form from DC won't self-extinguish from a zero crossing (because, of ...
- 38.5k
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