This circuit is from an old Popular Electronics, but it can be easily implemented nowadays, even adapted to act as a shield. The circuit has the frequency given by C1 and adjusted in R1.
June 2016 - It can be obtained from Mouser Electronics Power inductors for automotive use of...
El circuito de la figura es un regulador de corriente con ajuste en el rango de 0 a 3 ampères. El...
This is a commercial circuit of a transistor amplifier of some watts with the OC30 transistor. The 12 V...