This circuit is from Philips' 60s documentation. The circuit can be applied to modern operational amplifiers. The power supply must be symmetrical.
This circuit causes an LED to flash at a frequency determined by the capacitor. The circuit is...
This simple 1-transistor receiver has speaker listening. We found it in an article published in...
The integrated circuit used is equivalent to the 555 and the transistor can be the BC558. R1 and...