FM Stereo indicator lamp in Tuner circuit

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Thanks Mooly...good to hear my calculator and formulas were right!
I think I'm going to try the lamps and if they all light up....I'll call it good.
This Roberts receiver is not a high end machine by any stretch and I've been very thrifty in it's repair. But it sounds great now and this was the last thing to fix before I button it back up and I think it will be fine for another few years.
Just another unit saved from the dumpster....
It was a nice simple unit to work on for me and I didn't have to spend much, learned a lot and had fun doing it!
The lamp analysis was the icing on the cake!...and I thank all for their comments and patience. :)
 
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Thanks Mooly...good to hear my calculator and formulas were right!.....

Your welcome:)
And its great to work on purely discrete circuitry too. There are always ways and means and options available, something that isn't so when its stuffed full of IC's and the like.



A breadboard experiment may be the best way to go. A look at flicker fusion threshold supports both our positions. I didn't know it could get so complicated... a real eye-opener.:)

A lot read there. I did a quick test before seeing all that and this is what I got. A red LED fed via a sinewave source.

Direct viewing straight at it and I consistently got 41hz as the point I would be unaware it was AC fed.

Edge of field (corner of the eye) and it was around 52hz

Head moving from slow to quick. That took the 52hz up to around 2Khz.

Moving the LED quickly. That pushed the upper limit to easily 7Khz. If I could have soldered wires to the LED rather than holding it all together (so I could move it even faster) then that figure would be higher still.


So there we have it :)
 
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