microcomputer power supply protection - overvoltages and short-circuits need no longer be a danger to microcomputers

july/august 1984 overvoltages and short-circuits need no longer be a danger to microcomputers microcomputer power supply protection The 12 V supply is protected in much the same way. When the voltage reaches about 12.7 V thyristor Th2 conducts and shorts the 12 V line to ground. The supply to the coil of the relay is then cut off found (and cured) the supply can be switched on again by pressing push button S1. An "off" button has also been provided, which should be of particular interest to ZX users as these computers do not have an on/off switch. Constructing this circuit is aided by the availability of the printed circuit board shown in figure 2. It is prin- cipally intended for use with the microcomputer power supply pub- lished elsewhere in this issue and it can be connected directly to that cir- cuit"s +5 V and +12 V outputs. If you wish to use this protection with a computer with no 12 V supply line the 12 V section can simply be left out. The relay will then have to be chan...