It's a sign!!!

[Mickster]

Was just playing with a BFO circuit and when the power supply was switched off, I observed this:

It's a sign.... I have to go to Area 51 on the 20th of September and join the unwashed masses, they are hiding alien technology from us and we demand to see it!!!!!

They can't stop us all!!!
Wish me luck.



P.S. Anyone know how to get pure sine waves?

 

[JimB]

P.S. Anyone know how to get pure sine waves?

A lot depends on what you are starting with, but generally speaking, filters work well.

JimB

 

[Mickster]

A lot depends on what you are starting with, but generally speaking, filters work well.

JimB

Thanks Jim, just tinkering around with a basic BFO circuit on a BB (Sorry AG) and using less-than-ideal coils (Automotive ABS solenoids) in the LC tanks, as they are pretty close to each other without winding my own. A few brass strips on one of the solenoids nulls it, but BB jumper wires and mis-matched caps/transistors are also likely not helping much with the pattern.

Here's the 'before' pic:

Just thought it was funny to see the 'UFO' when the PSU was turned off.
As an aside, just came close to crapping my pants when I knocked the brass strips off and the piezo started buzzing....

Anyway, I'm looking for sponsors to pay for my trip to Area 51, I've got a Kodak Easyshare and promise to get some great photos.

 

[Ian Rogers]

Years back, I had to produce a perfect sine wave generator.. 0 ~ 1vpk .. I don't think it was perfect but I used a wein bridge oscillator with two diodes in the feedback...

It was close but a pk to pk of 1 v was all they needed..

 

[Nigel Goodwin]

Years back, I had to produce a perfect sine wave generator.. 0 ~ 1vpk .. I don't think it was perfect but I used a wein bridge oscillator with two diodes in the feedback...

Obviously the requirement WASN'T for a 'perfect' sine wave

Diodes make it 'easy', but distortion is fairly high - better to use a small light bulb if you want high quality.