High frequency oscillators may be needed in various types of industrial and consumer applications such as instrumentation, test benches and jousting, etc. Oscillators of this type are also important for repairing AM or FM radio devices, receivers, tuners, intercoms, and others. A signal generator capable of producing high frequency signals with good intensity is essential. The device that we describe in this article produces a signal of good intensity over a wide range of frequencies and is modulated with an audio tone, which greatly facilitates its use that require signals of this type. If the reader does not yet have a small signal generator or even a signal injector, he cannot miss this opportunity to count on the help of this type of equipment from now on. On the other hand, if you need a stable circuit to generate high frequencies, this configuration can be very useful.
A simple, fast and efficient process of finding problems with AM and FM radio receivers, intercoms and other communication equipment, is to apply an RF signal to its input. By the way this signal is reproduced on the speaker (or phone) we can find the defective stages. This same signal can also be useful for making adjustments to the different stages of equipment of the same type, leading to better performance. The L1 coil consists of 200 turns of fine enameled wire (28 to 32) in a 10 cm long ferrite rod with approximately 1 cm in diameter. The coil L2 consists of 30 turns of the same wire, wound on the side or over L1. Transistors support equivalents, and resistors are 1 / 8W with 5% or more tolerance. Capacitors can be polyester or ceramic. For power supply, 2 small batteries in an appropriate support can be used.
