This primitive solar radio was found in a Gernsback publication from 1960. The transistor is made of germanium of the time and the earphone is magnetic with high impedance.
We can implement this filter with more modern equivalent operational amplifiers, since the LM110 is...
We found this circuit in a 2005 documentation. The circuit allows the automation of a gate through...
The amplifier presented with the TDA2003 can provide a power of up to 10 W (rms) in a load of 2...