This analog frequency meter for low frequencies was found in Radio Electronics magazine from July 1958. The circuit has several scales with the frequencies indicated in 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...