Frequency measurement with tuning forks....

rons · Jan 27, 2018

I came across a Frahm frequency meter today. It is a pretty cool device to monitor line frequency. The 58-62 Hz one I looked at is this one:

Frahm Frequency meter - Google Search

You can read about it here:

The vibrating reed frequency meter: digital investigation of an early cochlear model [PeerJ]

JST · Jan 27, 2018

I have a couple like that. They actually work quite well as a readout on a generator.

rons · Jan 30, 2018

I can buy a 58-62 Hz James Biddle meter for $15 marked down by 1/2 to $7.50. Is it worth it?

This particular one (probably like most of them) has cracks in the paint or porcelain on the ends of the vibrating bars. If a chunk chips off then the resonant frequency of a bar would change. The end of the bars on the inside of the meter have little adjustment screws for tuning the action. Cool idea.

TDegenhart · Jan 30, 2018

Amazing what one can do without electronics. The old boys were pretty sharp. Same idea that was used in older ham and commercial radios to create a mechanical band pass filter for speech.

Tom

Monarchist · Jan 30, 2018

TDegenhart said:
Amazing what one can do without electronics.

?? Those ARE "electronic". The vibration / not is induced by an electromagnetic field driven off the gen head output, not by vibration from the IC engine block or such.

One reed will be in near-perfect resonance, hence "damped", those either side of it not so much. THAT part is a mechanical effect - the translation to gross-movement "enough" that the Mark One Eyeball can easily detect and discriminate.

TDegenhart · Jan 30, 2018

What I was referring to is the lack of tubes or transistors. Just like the old iron vane volt and ammeters were true RMS.

Tom

JST · Jan 30, 2018

Yep.... "Electric" is not the same as "electronic".

Monarchist · Jan 30, 2018

TDegenhart said:
What I was referring to is the lack of tubes or transistors. Just like the old iron vane volt and ammeters were true RMS.

Tom

I can identify with that. Hot-wire meters as well... Time was.. input impedance / circuit loading just wasn't all that picky!

jim rozen · Jan 30, 2018

I can state with 100% certainty that not only do those frequency meters rely on the movement of electrons
for their operation, but the entire instrument is simply chock-a-block full of those amazing electron particles.
Completely electronic from top to bottom, side to side.

Really tough to find something without them inside these days!

Tony Quiring · Jan 30, 2018

The old radios for land mobile had reeds that were used for audio control or CTCSS that were a fine tuned coupled transformer very accurate.

The older version of these meters ate basically a coil connected across the output voltage with tuning fork like metal reeds that react to the frequency of the field.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Monarchist · Jan 30, 2018

jim rozen said:
I can state with 100% certainty that not only do those frequency meters rely on the movement of electrons
for their operation, but the entire instrument is simply chock-a-block full of those amazing electron particles.
Completely electronic from top to bottom, side to side.

Really tough to find something without them inside these days!

Not hard at all. Most self-respecting atoms wear their electrons on the outside, and at rather a goodly distance as relative sizes go.

Atoms have it right. I mean, who'd want little critters with such shocking behaviour prowling about at random in their underpants?

9100 · Jan 30, 2018

Monarchist said:
Not hard at all. Most self-respecting atoms wear their electrons on the outside, and at rather a goodly distance as relative sizes go.

Atoms have it right. I mean, who'd want little critters with such shocking behaviour prowling about at random in their underpants?

Atomic nuclei usually contain neutrons which can emit electrons to become protons. Does a neutron contain an electron or does it generate one when it changes? If the former, then nuclei also have electrons and we have to fall back on various muons, mesons, etc. which may not always contain electrons.

Of course, we still have not determined the number of angels on a pinhead.

Bill

Monarchist · Jan 31, 2018

9100 said:
Atomic nuclei usually contain neutrons which can emit electrons to become protons. Does a neutron contain an electron or does it generate one when it changes? If the former, then nuclei also have electrons and we have to fall back on various muons, mesons, etc. which may not always contain electrons.

Answer is probably on the internet. Memory sez they are generated.

As former "minder" of a rather largish number of W31 warshots - it also sez you really don't want to be in the zone when it is going on at a grand scale!

Of course, we still have not determined the number of angels on a pinhead.

I thot Gorton had already engraved dance-cards for the lot of them?

Modern nano-tech, OTOH, is borderline amazing, probably re-soling their footwear by now.

jim rozen · Jan 31, 2018

"Does a neutron contain an electron or does it generate one when it changes?"

Yes....

Monarchist · Jan 31, 2018

jim rozen said:
"Does a neutron contain an electron or does it generate one when it changes?"

Yes....

BTW .. didja remember to feed that damned cat?

TDegenhart · Jan 31, 2018

That was Schrödinger. Different topic.

Tom

Monarchist · Jan 31, 2018

TDegenhart said:
That was Schrödinger. Different topic.

Tom

Keep up in the back. Can't be far, wot with Lorentz-Fitgerald as it are.

Thread has become all about how rapidly we can re-tune the topic...

Idle minds keep the Devil sitting on his hands. Or something like that.

JST · Feb 1, 2018

Here yah go.... two different meters plugged into the 60 Hz line. Did not have a variable frequency source of sufficient power handy to hand. The dials are both whiter than they appear, the color is partly due to using low light to get the canera to a slow enough shutter speed so as not to just freeze the motion of the indicator.

Both have similar resolution, one has a wider range than the other.

Ziggy2 · Feb 2, 2018

Monarchist said:
BTW .. didja remember to feed that damned cat?

Only the live half.

rons · Feb 4, 2018

JST said:

When I bench tested the Frahm meter both indicators vibrated between 59 and 60, which means 59.5Hz. Intermediate frequencies (between the lines) should make the vibration displacement of the markers at less than full height, I would think.

Frequency measurement with tuning forks....

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