We are proposing to develop a new theoretical method to compute the size and nature of fluctuations in quantities like the electronic charge transported across a device and the energy dissipated, when the device is switched. An accurate theoretical description of these fluctuations will become increasingly important for the development of future electronic devices as these become smaller. We will concentrate on providing an account of devices already under current or proposed experimental investigation. In describing the operation of small devices it is important to take account of the fact that the energy of light and the charge of an electron come in indivisible packets called quanta. The effect of this on fluctuations is much greater the smaller the devices and the smaller the numbers of electrons or light particles involved. It is like being hit by raindrops. You notice the difference between being hit by 2 or by 3 drops per minute, if the average is 2.4 raindrops per minute, much more than the difference between being hit by 3500 and 3501 drops when the average is 3500.4 per minute.The examples we propose to study include:1. Some single photon detectors in which the conductance of a narrow channel changes when the energy of an incoming light particle is absorbed.2. Some devices which are predicted to achieve the absolute fundamental minimal limit for fluctuations when the voltage across them is controlled in a certain way;3. Some small devices in which the conductance is controlled by the state of a nearby impurity. This impurity changes between its two possible configurations as it absorbs and emits energy from some background source of heat. For this particular case, it is important for us to develop our method to handle the effect of temperature.