charles wrote:

In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.



--

Roger Hayter