The transistor can be a BC548 and the coil has the following characteristics for 1 MHz. L1 has 80 turns of wire 28 in a ferrite rod and L2 of 30 and 40 turns.
We found this circuit in a 1986 publication. However, as it is based entirely on 555 integrated...
We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors...
In this circuit a 12 V lamp or LED blinks with the music signal applied to the input. R depends on...