Articoli rivista
Note di elettronica
Anno XXVII - n.2 - aprile/giugno 1994 Alcune considerazioni sull’adattatore di tensione capacitivo
Some comments to the paper “Un adattatore di tensione fra lo standard americano e quello europeo” are here presented. A more detailed analysis in terms of complex impedances is worked out, and some suggestions for a safer handling of the device are given. […]
Anno XXIX - n.2 - aprile/giugno 1996 Amplificatore di condizionamento per Universal Lab Interface
The cheap circuit here described makes possible to process signals in an arbitrary range (e.g. ± 10V) without an external supply, using the positive supply (+5V) available on the U.L.I. interface connector. […]
Anno XXVII - n.4 - ottobre/dicembre 1994 Cos’e’ un lock-in? a che cosa serve? come costruirne uno?
A short description of the lock-in technique gives an idea of the working principle of these useful devices, that are widely used in weak signal detection, but rarely treated in introductory courses. Simple and cheap circuits, that may be easily assembled by the student are suggested, […]
Anno XXIV - n.4 - ottobre/dicembre 1991 Interfaccia cronometro per personal computer
A time-measuring device that can be connected to any MS-DOS PC through the standard CENTRONICS parallel printer’s connector is described. The start-stop sensors can be either electromechanical or electronic. A dedicated software controls the device’s operation and status. […]
Anno XXVI - n.1 - gennaio/marzo 1993 Interfaccia per misure on-line nel laboratorio di fisica con computer Apple
We describe hardware and software of a low-cost interface board designed to allow easy measurement of analog quantities and time intervals by Apple IIe computer in the physics laboratory. The device includes a timer, a four channel A/D converter and the corresponding conditioning circuits for data acquisition. […]
Anno XXX - n.2 - aprile/giugno 1997 Misure di momenti d’inerzia
The inclined plane is used to evaluate, on the basis of. energy conservation, a moment of inertia. In a first step the coefficient of rolling friction is found; finally, using simple experimental equipment the purpose is achieved. […]
Anno XXVIII - n.2 - aprile/giugno 1995 Misure di resistenza elettrica ottenute da misure di tempo con un calcolatore collegato on-line
A simple interface, performing measurements of electrical resistance by evaluating the length of a pulse with computer on-line is described. The circuit is particularly simple so that it can be discussed even with pupils of the second year of secondary school, […]
Anno XXVI - n.2 - aprile/giugno 1993 Un adattatore di tensione fra lo standard americano e quello europeo
A commercial adaptor between the US and European mains standard plugs can be modified to act as a voltage transformer. No heat is produced because a reactive and not a resistive divider is used. The device is a simple example of the Ohm’s law in AC circuits. […]
Anno XXVIII - n.4 - ottobre/dicembre 1995 Un esperimento dimostrativo sul fenomeno della fotoconducibilità, cioè della diminuzione di resistenza elettrica di un semiconduttore indotta dalla luce
This experiment demonstrates the photoconductive effect for Si and Ge samples illuminated by quasi monochromatic light. The vanishing of the effect for longer wavelengths allows a qualitative estimation of the fotonductive threshold which is related to the energy gap of the material. […]
Anno XXIX - n.3 - luglio/settembre 1996 Un sistema a fotocellule per esperienze di meccanica
This note describes a system based on photogates and interfaced to a PC that can be particularly useful in physics experiments in which the description of objects’ motion is relevant. The PC role is twofold: on one side it is the system timer, […]
Anno XXVI - n.4 - ottobre/dicembre 1993 Verifica di un modello della fotoconduzione nei semiconduttori, basato sull’analisi della risposta alla luce, in regime statico e dinamico, di una fotoresistenza al CdS
Photoconductive CdS cells are cheap solid state devices, suitable for a first understanding of the optical properties of semiconductors. This work presents two experiments, concerned with static and dynamic behaviours of a CdS cell, which allows us to verify simplified model explaining semiconductors’ […]