Theory of a Monolithic, Null Device and Some Novel Circuits

An important trend in modern electronics is toward decreased size and increased reliability of electronic systems. This paper discusses a new simple structure which performs the function of a twin-T network, i.e., a null output is produced at a single frequency. This new structure has the advantage of being very small, simple to fabricate, and easy to use in conjunction with transistorized circuits. The theory of operation of the device, experimental verification of the theory, and some circuits containing the device is also discussed. The structure has been found useful to create a high-Q tuned amplifier, an oscillator, and a threshold transducer. The physical simplicity of the structure should result in a high degree of reliability and uniformity of response. It should be noted that the structure can be fabricated from semiconductor materials and is thus suited to "molecularized" or "integrated" solid state systems.