This circuit was found in the November 1966 issue of Electronics Now magazine. It uses an LDR as a sensor and has a Bargraph scale with the well-known LM3914.
When the control level is increased from 0 to 1 (LO to HI), this circuit is activated, which...
This 1950's circuit used one of the first commercial transistors and had two stages for audio...
This amplifier can be powered with voltages from 9 to 14 V providing 7W of maximum power under a 8 ohms...