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We found this circuit in a PE Hobbyst Handbook from the 90s. The components are common, except the Geiger tube. The transformer is also a component that requires care when choosing.
We found this relaxation oscillator in a 1967 General Electric documentation. The frequency is given...
This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit has...
Although the BD135 transistor is not specifically for RF applications, some of them can easily...