Abstract: The present invention has provided a new diode and transistor by employing the characteristic of the tunnel diode. The new diode and transistor are field interacted and can be a solarcell, light sensor, thermal device, Hall device, pressure device or acoustic device which outputs self-excited multi-band waveforms with broad bandwidth. The present invention has also revealed a precisional switch which can works at high speeds and a capacitor whose capacitance can be actively controlled.