This circuit was obtained from a 1964 magazine and has some interesting features such as the input bias of the first transistor made by the signal itself. Care must be taken not to invert the diode. R1 should be obtained experimentally for higher resistor performance in the range 2k to 47k .. The coil consists of 100 turns 28 of wire on a ferrite rod and the transistors may be the BC558. The transformer is the output type for transistor radios. The circuit runs on 6 to 8 V power.
