.005pf capacitor anyone?

[ajhawkins]

I was browsing throught my schematic for my Eico HFT-90 tuner, in the process of creating a small bom, ran across .005mmf which I believe is a .005pF capacitor is it not? I look all over couldnt find such a beast. Anyone know where to find such an odd part?

 

[EC8010]

No, it's 5nF.

 

[seangoesbonk]

... a .005pF capacitor is it not? ...where to find such an odd part?

You can make a 5 femtofarad capacitor by placing 2 wires within a foot of each other.

But really, it's probably actually 0.005 mF or 0.005 uF. You're not supposed to post the schematic because of the whole copyright thing, but perhaps you can show us a small section of it, so that we can figure it out...

 

[ajhawkins]

Schematic

I found it on the web so I dont think EICO will sue *knock on wood*

http://engr.uark.edu/~lar/hft90s.gif

its too large to upload with the 100k cap.

 

[Sch3mat1c]

"mmf" generally means micro-micro-farad, or yes indeed, picofarad. Must be a typo.
*I think* it's before the days of standardized Greek symbols for orders of magnitude (µ, etc.), in any case it doesn't mean "mili-mili-force" as today's symbols would say. )

.005 would generally refer to µF, or 5nF, or 5,000pF.

<Schematic finally downloaded> Ah, that is weird... huh. Maybe they did mean "mili-mili" for some strange reason.
Nah that can't be, cuz they have "mfd" there as well...

Tim

 

[EC8010]

That's weird. As you say, mm usually meant micro-micro, but there's just no way you can make a 0.005mmF, or 5fF capacitor - 5pF tends to be +/- 0.5pF. On the other hand, three typos are odd too. Perhaps comparing the component's value with other circuits of that era will solve the problem...

 

[AudioFreak]

well these days mfd usually means millifarad ... that is to say 1/1000 farads but given that list, I dont believe I've ever seen a 10uF disc cap so maybe it is micro and micro-micro after all...

 

[theChris]

possibly is it a typo? mmfd, mfd, i mean it is possible someone just got happy with the m key?

 

[Netlist]

Both links with schematics and pictures should reveal the answer.
http://home.earthlink.net/~eico_hf81/eico_hft90.htm
http://home.earthlink.net/~eico_hf81/links.htm

IMHO 0.005mmf is 5pF

Greetings
/Hugo

 

[ghettorigged]

capacitance meter

anyone have plans for a capacitor meter down to 1pf Yeah I'm thinking I'll just leave them alone since I have no way of knowing for sure the value.................thanks for your input guys

ah

 

[Borc]

http://www.hw.cz/constrc/lc_metr/

I made it and will never regret. Cheap (20$)and accurate to about 0.5 uF, L-meter works flawlessly.

 

[EC8010]

Re: capacitance meter

Anyone have plans for a capacitor meter down to 1pf?

Not quite plans, but I believe that a Blumlein Bridge can easily do what you need with great accuracy. UK Patent No 323,037 "Alternating Current Bridge Circuits" 13 September 1928 A D Blumlein.

 

[Netlist]

Re: Re: capacitance meter

UK Patent No 323,037

Any link to that patent?

/Hugo

 

[EC8010]

Yes! It took a bit of time, but:

http://doramusic.com/patents/323037.htm

 

[Netlist]

Yes! It took a bit of time, but:

To me this is still a 'fast' reply.

Thanks

/Hugo