[ARC5] JFET in ARC-5 TX oscillator socket

[Bob Macklin]

When JFETs came out in 1962 we were paying $50ea for them and destroying
several per day trying to learn to work with them.

Bob Macklin
K5MYJ
Kent (Seattle), Wa,
"Real Radios Glow in the Dark"

----- Original Message ----- 
From: <mstangelo at comcast.net>
To: <sbjohnston at aol.com>
Cc: <ARC5 at mailman.qth.net>
Sent: Thursday, July 09, 2009 7:03 PM
Subject: Re: [ARC5] JFET in ARC-5 TX oscillator socket


> When the MOSFETS first came out the prices were high; I can believe it.
>
> Dual gate mosfets followed the single gate 3N128 Insulated Gate mosfet.
They were popular because the second gate could be to control gain in
amplifiers. The Dual Gate MOSFETS were also used as mixers.
>
> As someone mentioned, the thin insulation was susceptable to damage from
static discharges. The FETS were packaged with a coil of wire shorting all
leads. You were advised to remove the short after the transistor was
installed in the circuit.
>
> RCA came out wth a line of dual gate MOSFETS with input protective diodes,
the most popular one being the 40673. This FET was a popular device in
Heathkit solid state kits. It still is a popular part, and like lots of
discontinued parts, fetches a premium price these days.
>
> Mike,
>
> N2MS
>
> ----- Original Message -----
>
> From: sbjohnston at aol.com
>
> To: ARC5 at mailman.qth.net
>
> Sent: Thu, 9 Jul 2009 03:30:34 +0000 (UTC)
>
> Subject: Re: [ARC5] JFET in ARC-5 TX oscillator socket
>
>
>
> WA5CAB wrote:
>
>
>
> >the last JFET's I actually bought were around $15 each.
>
>
>
> That's exorbitant.  Sure those weren't dual-gate MOSFETs are something
>
> else really rare?
>
>
>
> Right now Mouser has the MPF102 JFET for 10 cents each, single
>
> quantity.   Radio Shack has MPF102s on the wall for $1.29 each.
>
> Newark sells 2N3819 JFETs for 11 cents each.
>
>
>
> So I don't think you can really say that cost is the reason not to
>
> experiment with a JFET VFO using ARC5 parts.
>
>
>
> Steve WD8DAS
>
>
>
>
>
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