56～484 high frequency oscillator

The high-frequency oscillator shown in the figure can be used as a high-frequency signal generator. By selecting different capacitance values, a high-frequency sine wave can be generated in the range of 56 to 484kHz. The circuit has the characteristics of good waveform, high frequency stability, and low output impedance.

Component selection:

Transistors VTl, VT2: 3DG6D, 65≤β《115, VT3, VT4: 3DGl308, 60≤β≤85. Semi-adjustable capacitor C4: CCWX-3-5/20pF. Quartz crystal SJT: BE-42. K: JZX-10M (small relay). Light-emitting diode VD4: BT-605 (red, green double color). Transformer T: MXD-2000 ferrite, GV-30×19 magnetic core. Ll-2Φ0.21mm high-strength enameled wire, wound 133 turns, L3-4Φ0.21mm high-strength enameled wire, wound 11 turns, L5-6Φ0.21mm high-strength enameled wire, wound 80 turns. The nominal power of the resistors is 1/8WRJ except R27 which uses 1/2WRJ type. The parameter values ​​of other components are as marked in the figure, with no special requirements.

The relationship between frequency and capacitance value is shown in the following table.