Hi All, With regards to John McClelland's recent posting about
the speed control for the PPCo vacuum pump kit (MMDigest 20.11.28),
the schematic he provided shows the "interactive" circuit that many
people have complained about for many years. In order for the circuit
to have two "independent" settings, R2 and R3 cannot be wired in
parallel. Here is a schematic of a controller with two completely
independent settings.

Musically,
John A Tuttle
Player-Care

 [ Dual-Speed Controller
 [ https://www.mmdigest.com/Attachments/20/12/02/201202_012153_dual-2.jpg