This circuit with different colored indicator LEDs has an expanded scale. We found it in the March 1992 Radio Electronics magazine. For an adjustable range of 0 to 10.5 V.
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...