The simplest of all devices on tunnel diodes are generators. In unlike transistor generators, they don't need a special chain feed feedback signal, and therefore the scheme, and the design is very simple. A diagram of the generator shown in the figure. The resistor R1, the diode VD1 and the capacitor C1 form a voltage operating point of the tunnel diode. It equal to the direct voltage drop at the open junction diode VD1, and is in largely stable with changes in battery voltage. Working the point is in the falling phase volt-ampere characteristics of a tunnel diode VD2.
To the tunnel diode VD2 is connected a low-frequency oscillating circuit L1C2, where and are excited oscillations. Directly from this circuit the voltage LF served on high impedance phones BF1.
For normal excitation of the generator it is necessary that the peak current of the tunnel diode was within 1...2 mA, the peak voltage was 60... 100 mV. Consequently, the generator can be assembled on a tunnel diode of any type with the specified parameters. In addition, it is necessary that the resistance of coil L1 does not exceed 5 Ohms, and its inductance would be several tens of millihenry. The author used the W-shaped magnetic core of transformer steel cross section 0.5 cm2 on the frame which coil to a coil wound 400 turns of wire PEL diameter of 0.25 mm. as the coil L1 can also try to use half of the primary winding or the secondary winding output transformer from a transistor radio. To obtain the desired tones and fluctuations in the capacitance of the capacitor C2 must be chosen within 0,01... 1 µf.
As a power source for a generator, you can use silicon photocell, developing current 3...4 mA. For this purpose it is connected instead stabilizing diode VD1. The resistor R1 and an external power source in this case 't need. The generator starts to work in bright light solar cell.
The scope of the proposed generator is quite wide. It can serve the signal source when establishing a low-frequency equipment, in the study of Telegraph Morse code, and when powered by solar cell - indicator a well lit room or workplace. During the development of the generator source: information adapted from: N. Goryunov.N. and other Circuits using tunnel diodes. - M.-L.: "Energy", MRD, 1965.
Author: S. Kovalenko, Kstovo, Nizhny Novgorod region