| Popis: |
Circuit breakers have recently started to replace fuses in common use; the authors therefore thought it might prove instructive, as well as entertaining, to study the action of these two devices using a microcomputer as a storage oscilloscope. In particular, the time taken for each to react to various overloads could be determined and compared. For this study only fuse wire and circuit breakers rated at 5 A were considered, but even so currents up to 13 A were needed for a fair comparison. The circuit used consisted of 12 NiFe cells connected in series with an ammeter, a rheostat, a small fixed resistance, a switch and the device to be tested. A fast analogue-digital converter was connected in parallel with the small fixed resistance and signals from this were fed directly to the user port of the microcomputer, Thus the PD across resistance could be monitored and hence the variation of current in the circuit followed. |
