| The mains filter described in ‘PC Topics’ (April 1998) could do with two useful additions: a fuse monitor and a voltage indicator. The f...
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| The alarm uses a pyrosensor to detect the presence of animals or human beings by changes in hear radiation.
| Many motorcycles have no temperature gauge - which means that their riders have to guess whether the engine is hot, cold or lukewarm (b...
| Although it has no detector or alarm actuation device of any kind, the present circuit may still function as a deterrent against car thi...
| The display is intended as a turning indicatoror a VU meter on a stereo FM radio. The first function is selected by pressing S1 (which m...
| This is one of the simplest twilight switches ever published in this magazine. When it gets dark, the value of light-sensitive resistor R...
| A continuity tester is very useful for checking printed-circuit boards. It indicates a sound connection by a squeak from a buzzer; there...
| Although most petrol-engined cars and lorries have a rev counter as standard, that is by no means the case in diesel-engined motor vehicl...
| The circuit in the diagram enables the monitoring of two temperatures, t1 and t2. The sensors are NTC reststors R3 and R4, which may be...
| When a bicycle speedometer must be rugged, accurate and, above alt novel and a Iittle unusual, the 'high-rech' computerized LeD units fou...