This control for 1/15 HP motors with 5,000 rpm for 115 V power grid was suggested by a Motorola circuit manual from 1968. The SCR supports more modern equivalents.
The cut-off frequency of the filter shown in the figure can be adjusted to values between...
This circuit was found in a Popular Electronics from the 90s. The components used are all common...
This circuit uses a dual floodgate MOSFET not very easy to obtain today. Its handling is very...