We found this circuit in an old documentation. The operational can be of any type and the frequency is given by the formula next to the diagram.
This well-known circuit version of the siren was obtained in a Colectro Handbook from the 70s. The...
This 2mA source was found in a 1968’s Philips documentation. The transistor may be the BC549. |...
This sensitive medium wave (MW) radio pick up the local station without the need of an external...