Using two 741 operational amplifiers, this low-pass circuit has a cutoff frequency of 10 kHz. We found it in an article in the magazine Electronics Now from August 1993.
When the input voltage is higher than 2/3 of the power supply voltage the green LEDs glows. When...
This is a conventional alarm that uses NO and NC type sensors for doors and windows. The circuit is...
This circuit was obtained in a 1972 RCA power transistors manual. The transistor admits...