This 100 second timer was found in the September 1992 issue of Radio Electronics magazine. The circuit has two timing ranges and time adjustment at R6.
This TTL circuit is from a Radio Electronics magazine from February 1973. The circuit must be...
Common operational amplifiers like the TL series, CA3140 and others can be used in this circuit...
This circuit uses only two common transistors and provides good audio power in a speaker. Readers who...