This circuit was obtained in a Hands-On Electronics from the 90's. The circuit turns on one LED at the end of the timer, erasing the other. The timing can be increased by changing C1.
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...
This 10 mA microammeter circuit can measure currents of 50 uA. The circuit is from a publication from the...
This receiver was found in an article in Electronics Now magazine in March 1994. The coils are...