Electronics > Projects, Designs, and Technical Stuff
Need some help building a circuit involving switchs and relays
Ian.M:
Hmmmm . . . I don't like the voltage drop for the optoisolator solution.
I'd experiment with using a common mode choke as a saturating 1:1 current transformer. Once you've got an isolated and limited signal, you've got a lot more options. Core saturation lets you use a fairly large burden resistor for a decent amplitude at 24mA RMS without the high voltage drop issues when passing several amps.
Shaydzmi:
--- Quote ---Why did they put in those bypass resistors?
Did they have their own measurement system for any of the bulbs going on?
--- End quote ---
They put them to ensure continuity if the bulb burns.
--- Quote ---If you wanted to make things easier and you could tolerate a bit more drop on the voltage to the bulbs:
--- End quote ---
It doesn't matter, as long as I have enough voltage to glow the bulbs, it's OK.
Shaydzmi:
--- Quote from: Ian.M on May 26, 2020, 04:10:35 pm ---Hmmmm . . . I don't like the voltage drop for the optoisolator solution.
I'd experiment with using a common mode choke as a saturating 1:1 current transformer. Once you've got an isolated and limited signal, you've got a lot more options. Core saturation lets you use a fairly large burden resistor for a decent amplitude at 24mA RMS without the high voltage drop issues when passing several amps.
--- End quote ---
A little schematic diagram would be better for me to understand as a beginner.
Benta:
Much simpler: let each 24 VAC line run through a current transformer. Detecting current/no current on the secondary side is a simple exercise, and you even get isolation for free. I'd suggest a 1:50...1:200 turns ratio, but it's uncritical.
https://www.quora.com/How-is-a-current-transformer-connected
Renate:
--- Quote from: Shaydzmi on May 26, 2020, 05:04:30 pm ---
--- Quote ---Why did they put in those bypass resistors?
Did they have their own measurement system for any of the bulbs going on?
--- End quote ---
They put them to ensure continuity if the bulb burns.
--- End quote ---
Yes, but that presumes that they have interest in continuity.
I can't believe that this loom? has 168 "thread out" indicators and no common indicator.
Was that an option that wasn't installed or got broken?
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