Variable duty cycle and frequency with a 555

[josephkk]

We know you have one. Dung beetles are some of nature's scavengers,
just like shellfish. they live off the wastes of other creatures. Then
some people eat shellfish.

Some do, more don't. Now catfish is a real dung eater. Don't trust me,
check it out for your self.

?-)

 

[captoro]

Just in case you are still reading, the EMI issues come mostly from edge

speeds rather than fundamental frequency.



?-)

edge speed ??? you mean harmonics ??

K

 

[Martin Brown]

The obvious question is why would you bother?

edge speed ??? you mean harmonics ??

The faster waveform rise time means that the higher harmonics of the
fundamental remain significant. In the limit that the waveform becomes a
delta function like spike then all harmonics are present with equal
weight. A real narrow pulse has finite width. I presume this is a device
designed to destroy MOSFETs and CFLs in roughly equal numbers!!!

BTW be careful if you end up flashing bright lights at frequencies in
the 5 to 15 Hz range as if you are even slightly prone to epilepsy at
the wrong frequency you could end up on the floor twitching in a fit.

 

[Fred Abse]

I grew up on the Ohio River... I only eat "farmed" catfish ;-)

What do they feed those? Sure it ain't made from chicken droppings?

 

[josephkk]

edge speed ??? you mean harmonics ??

K

Not perfectly, but yes. The fast edges mean lots of high order harmonics.
To help with the idea 1 microsecond edges mean plenty of 1 MHz range
content, likewise 1 nanosecond edges mean plenty of 1 GHz range content.

?-)

 

[josephkk]

Here, in AZ, a number of fish "varietals" (and shrimp) are grown is
man-made ponds, with known good fish hatchery stock.

What they feed them, I don't know. But I understand the
chicken-dropping-fed variety are known as NOLA-style >:-}

Speaking of chickens, until my oldest son started raising chickens on
his ranch, I didn't know that chickens are carnivores... and they just
love any sort of bird or snake that gets too close, and scorpions are
their special treat ;-)

...Jim Thompson

Hmm. Make that omnivores, the eat grain as well as worms, grubs and
insects when they get feral.

?-)

 

[amdx]

Nope, the rest ain't the same.
He separates the functions and manages the ground currents.
The devil is in the details and often not shown on the schematic.

WOW! A video showing that he can flash a light.
Makes no claims.
Draws no conclusions.
I want the 7 minutes of my life back.

I find it difficult to read by that light.
Yes, it reminded me of my 7th grade English class,
Boring.
Mikek

 

[amdx]

What a horror. I am surprised that the CFL didn't emit smoke. I can only
find a lightning strike a worse torture for the internal driver circuit.
It is definitely worse that IEEE Class C impulse rating.

Use a full transformer with L-R series load, instead of a simple inductor
to model a motor. You will find a real motor jumpy and twitchy at the low
frequency range of your system.

?-)

I got the impression that the core was a little bit jumpy!

 

[amdx]

We need to create three new newsgroups:



and

sci.electronics.you.ask.i.won't.answer
sci.electronics.do.the.math
sci.electronics.i.don't.know.the.math
sci.electronics.phil's.angry.name.calling
sci.electronics.how.far.can.a.thread.drift
Mikek

 

[Spehro Pefhany]

sci.electronics.you.ask.i.won't.answer
sci.electronics.do.the.math
sci.electronics.i.don't.know.the.math
sci.electronics.phil's.angry.name.calling
sci.electronics.how.far.can.a.thread.drift
Mikek

How about solution-oriented newsgroups? Eg.

sci.electronics.555
sci.electronics.PIC
sci.electronics.sallen.key
sci.electronics.howland

Problems should be posted in an appropriate group for that solution.

 

[Ralph Barone]

sci.electronics.you.ask.i.won't.answer
sci.electronics.do.the.math
sci.electronics.i.don't.know.the.math
sci.electronics.phil's.angry.name.calling
sci.electronics.how.far.can.a.thread.drift
Mikek

sci.electronics.12.angry.men (plus or minus a few)

 

[Bill Sloman]

Then we'd need another group

sci.electronics.tell-me-how-to-define-what-I-think-I'm-trying-to-do.

You forgot:

news:sci.electronics.braying.donkeys ;-)

Mike doesn't realise that this is actually an alias of


set up for mutual admiration sessions between him and Jim.