This circuit was found in a 1965 Radio Shack documentation. The transistors are from that time. The circuit can be implemented with current transistors and lower voltage supply.
We found this circuit in a publication for radio amateurs in 1977. The circuit allows the...
This circuit was found in an American documentation from the 90's. The circuit can use almost any...
This circuit was found in an Electronics World of 1968, making use of components of the time, not...