Complete Electronics Self-Teaching Guide with Projects

The Armstrong Oscillator

The Armstrong oscillator shown in Figure 9.35 is somewhat more difficult to design and build. Here, the oscillations depend more on the extra winding on the coil than on any other factor.

Figure 9.35

Because of the large variety of transformers and coils available, it is almost impossible to give you a simple procedure for designing an Armstrong oscillator. Instead, the manufacturer specifies the number of turns required on the coils, which guarantees that the oscillator will work in its most common operation, at high radio frequencies.

Because of the practical difficulties, the Armstrong oscillator and its variations are not explored any further.