Subj : Re: Theremin
To   : Martin Ridgley
From : MIKE ROSS
Date : Thu Nov 09 2000 03:00 pm

"Martin Ridgley" wrote to "Mike Ross" (09 Nov 00  14:52:06)
 --- on the topic of "Re: Theremin"

 MR> Well, it probably falls under the heading of 'more information than
 MR> I really needed to know', but I've been casually interested in the
 MR> Theremin for some years now.  I've even considered buying, or
 MR> building one on occasion, so I found this quite fascinating.

 MR> Thanks...


I found a DXF of a very well designed theremin circuit but I also found
in my archives this simple experimental circuit you can toy around with.
Mind that it's not a very good theremin. It is basically educational in
nature, really just to show the working principles.


> Theremin
>
> Circuit diagram for a Theremin : the only musical instrument in the world
> (at its time) that could be played without touching it.
>
> Invented in the 1920's, by Dr. Leon Theremin.
>
>  Peter Knight             p.j.knight@uk.ac.bradford
>
>
> Theremin schematic
>
> From the book
> '103 Simple Transistor Projects' by Tom Kneitel, pp98-99
> Published by Rider, 1964
>
> This schematic is based on a post to sci.electronics by jmichael@vnet.ibm.com
> Schematic graphic by p.j.knight@bradford.ac.uk
>
>
> All transistors are PNP
>
>     S1
>     __   Q1
> 9V--  --e c-------------------------------.
>          b          !                     !
>          !      Q2  e---.   \!/       Q3  e---.   \!/
>          !              !    ! Ant1           !    ! Ant2
>          !    .---b    C1    !      .---b    C2    !
>          !    !         !    !      !         !    !
>         R1   .-.    c--+++---      .-.    c--+++---
>          !   ! !       ! !         ! !       ! !
>          !  R2 C5     C3 L1       R3 C6     C4 L2
>          !   !_!       !_!         !_!       !_!
>          !    !         !           !         !
> 0V-------+----+---------+-----------+---------'
>
> Q1   2N1097
> Q2,3 2N1264
>
> R1     180K
> R2-3    51K
>
> C1,2  200pF
> C3,4  200pF Trimmer
> C5,6 0.01uF
>
> L1,2  vari loopstick
>
> S1     SPST
>
> Connections to the collectors of Q2,3 are made via 5 way binding posts.
> Antennas are Lafayette F343 whips.
> Keep leads short. Cut shield connectors off 2N1264's. Place near AM radio
> Adjust 200pf cap at J1 until hissing noise, then 200pf at J2 for whistle,
> then back to 200pf at J2 for lowest pitch. Play with hands. Perhaps an
> ascii artist can draw from the description. Good luck.


.... Mad at your neighbor?  Buy his kid a drum!
--- Blue Wave/DOS v2.30
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