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What was your first circuit? Do you still remember it?

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NiHaoMike:
A "traffic light" circuit with 2 transistors that switched between red and green LEDs.

--- Quote from: bd139 on July 28, 2017, 10:47:02 am ---This was mine :)



--- End quote ---
I remember a similar project with a different kit that actually reacted to blowing on the microphone. Anyone else think it might be possible on the above kit by using the speaker as a microphone and the third transistor as an amplifier?

Sredni:
I remember: a wired telegraph. Two pieces of wood with a small lightbulb and a switch made with a flexible sheet of metal that controlled the other terminal's bulb. Very high tech.
For some reason, neither my parents nor my cousin's seemed to think that drilling a hole in the floor/ceiling to let the wire through was a good idea.

Adults. Go figure.

RJSV:
   Guitar Octave Pedal.
   Made a large breadboard set, 3 solderless breadboards using LM-324 OP amps and LM-339 analog comparators.  One half did the input, doing Analog to Digital, using only 4 bits.  That got clocked into RAM, those days the RAM was 4 bits by 256 locations, so I'd used 4 ICs to obtain 1 k samples.
Clocked in, at 8 khz, and clocked out, at 16 khz, for OCTAVE music sound.  (Try listen to older Wes Montgomery guitar talent).
   That circuit was missing a 'zero crossing' coordination; instead it just blindly circulated, the input counter registers, and output counter registers, for addressing the guitar sampling buffer, both operating in just a circular manner, rather than the more correct way, of starting or stopping each sweep, at a consistent zero crossing, to avoid 'glitched' output waveforms.
   More fascinating than the guitar sound, with octave higher 2nd note audible; that whole unsheilded breadboard RADIATED EMF to the surroundings.
That means, the circuit's own input got some trash, and, (sorry FCC) nearby TV receiver sets had hashy screen trash NOISE. ..Fascinating, and not really anticipated RF emissions.
   The memory addresss registers actually used a 2-port shared access to the little 256 X 4 bit RAM.

Kleinstein:
I remember is kind of rats nest with 4.5 V batteries and light bulbs and a single on/off switch. The strange part was the single switch could turn one lamp on and another off at the same time. Took me quite some time to understand how this could work with only an on/off switch.

vk6zgo:
Back when I was a kid, we lived out of town, lighting was kerosene lamps, radios were all valve battery sets, & the most "electrical" thing kids played with were battery "Torches" (flashlights).
After messing around with everything else I could wreck, I fixed upon the hapless torches, discovering that, yes, they didn't need the reflector to work.
This was also tied in with my obsession with making a movie projector, after finding an article on a magazine about making a film strip projector.
I didn't know the difference, so as 9 year old, had delusions about what I could make.

When we moved back to the city, at about 11, such things lost their appeal, cars were much more appealing, & I became a little revhead, as they were fun to work on.

Thus, it was not till I was around 14 that I built my first bit of electronics--a "one valve" regenerative radio which didn't work.
(Thinking back, I probably had the feedback winding connections reversed)

The next year, I made a better regen radio which  did work, although not as well as I would have liked.
A couple of years later, I made a proper superhet radio---a "mantel set" for my Mum, which worked Ok for some years.

I went off building stuff for years after that.

I keep planning to revisit those "regen sets" to see  if they were just crap designs, or if it was my poor construction techniques.

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