Audio Booster (CB6181E)

This reinforcing stages from a 1960s documentation. No information is given about the transformer and the transistor admits equivalents.

| Clique na imagem para ampliar |

Notch Filter (CB12169E)
This filter that rejects determines frequency (notch) was found in a Popular Electronics of 1993....
Double door bell (CB7559E)
Found in an Elektor from the 90's, this double door-bell drive circuit switches a relay by...
Sine to square converter (CB7329E)
Using a 555 this circuit was found in old documentation, but it is still valid. | Clique na imagem...