Telephone amplifier (CB8630E)

This circuit uses a pickup coil to take the signal from a telephone line without contacts. The circuit is from a 90s Popular Electronics.

| Clique na imagem para ampliar |

Stage with FET and Bipolar (CB6152E)
This circuit is from an Electronics World of 1967. The described calculations can be applied to...
FET MW Radio (CB12499E)
I found this circuit in a 1979 documentation. The phone must be at least 1k magnetic or crystal...
Medical thermometer (CB7880E)
This circuit of an old medical publication makes use of an integrated circuit of the time,...