Hey Dave,
Can confirm the same thing happens with a SGS THOMSON SOIC package 555!
Easter Eggs in everything. It's crazy.
I love Easter Eggs (on every date :p). In one of my projects containing an alphanumeretic lcd the "Easter Egg" was instructions for obtaining the source code.
Interesting.
Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
Lol, you can't be serious. Perhaps Dave should test this?
I think I should show this video to my digital circuits class today
Yep,
But it doesn't seem very stable on my end.... Will have to test again tomorrow to see if it works again
Lol, surely you can't be serious.
I am serious. And don't call me Shirley.
Wow, this is pretty cool! I'll see if I can give it a try.
Interesting.
Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.
Hans was a clever designer, I'm sure it's very subtle...
Dave.
It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
Awesome, will have to try it.
Hans was bought back to design the 7555, so makes sense he put something in that too.
Dave.
I wonder what would happen if you made a 555 out of discrete components.
Am I the only one that thinks April Fools??
Am I the only one that thinks April Fools??
Of course, lol, I can't believe we fell for it.
A question would be "how did he do it ?".
I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?
What didn't make sense to me was the frequency seemed to be changing slightly, yet he detected the modulation using a simple low pass filter which shouldn't work, so it should've been obvious something was a miss.
I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?
I can assure you, the scope leads were connected directly to the 555 as explained.
Dave.
The circuit doesn't match the schematic.
The pot is really 200R rather than 500R and then there's all those resistors connected in parallel.
The pot should also never be allowed to go too low otherwise it'll burn out the discharge transistor in pin 7 so there should be a fixed resistor in series with it.
I can assure you, the scope leads were connected directly to the 555 as explained.
Dave.
Is there a prize for figuring out how you did it?
It matches.
As mentioned, the values are approximate.
Only found a 200R pot in my kit, so used a series resistor as well.
The 1k5 is made with 3 resistors to tweak the value so I could get the range needed.
No trickery in the resistors at all.
Dave.
I hope there's a reveal coming up then.
and that's a normal 555 timer not some uC in DIP8 ?
I don't suppose Dave did something with Agilent scope heh.
Not just an engineer, but a magician also apparently.
and that's a normal 555 timer not some uC in DIP8 ? I don't suppose Dave did something with Agilent scope heh.
Yep, brand new bog standard National 555 timer.
Try harder!
Bueller?, Bueller?
Dave.