Scratch is the scratching noise that occurs mainly with old records. This high frequency noise is eliminated by the filter found in the February 1990 issue of Radio Electronics magazine.
The gain of this circuit is given by the value of R1 that depends on the current in the...
This hydromassage circuit was found in a 1967 General Electric publication. The SCR is according to the...
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...