This crystal or galena radio uses a germanium diode. C1 is an old radio variable and L1 has 100 turns of 26 or 28 wire in a 1 inch PVC pipe. The antenna must be a long wire.
This circuit is from a Popular Electronics from July 1990. The magazine no longer exists, but the...
Other operational amplifiers series, such as MC34072, MC34074, MC35071, MC35072, MC35074 d MC33071...
This gain 10 CMOS op amp was found in the May 1993 issue of Electronics Now magazine. It is...