This bandpass filter has a simple feedback system. The component values can be calculated using the formulas found in the math section.
This circuit activates an incandescent garden, balcony or showcase lamp when it gets dark, turning it...
This circuit is from an old publication of 1972 but can be mounted with BC548 transistors for 12 V...
This circuit is intended for the testing of junction FETs, providing several reading options...