program EPROM - with 25 V

After last year"s welcome drop in prices of good quality EP ROMs, computer enthusiasts have a great incentive for taking on more ambitious programming projects. Although normal operation calls for a 5 V supply voltage, 25 V is needed to program a 2716. In some types, the 25 V programming voltage need not be switched off while the operator checks freshly stored data. On the other hand, there are types for which the voltage has to be switched from 5 V to 25 V continuously. . with 25 V It therefore follows that a suitable EPROM power supply has to meet certain requirements: it needs to be straightforward, fast (often the speed is specified by the manufacturer as being, say, between 0.5 and 2μs), accurate (no danger of overshoot or undershoot) and short proof. The well-proven 723 voltage controller IC fits the bill perfectly. As the circuit diagram shows, the 723 is at the heart of an ordinary 5 V power supply. Preset P1 limits the reference voltage (pin 6) to 5 V and feeds the signa...