Morse Code Teaching Program For Electron And Bbc Computers

7 EE 64 November 1987 2,1 2C available. Moreover, if the tacho frequency is high enough-at least 2 kHz-the current feed- back loop is not necessary, per- mitting a saving in external components, as shown in Fig. 5. For applications where the TDA7272"s 1 A output capability is insufficient, high power opamp boosters such as the SGS L465 may be added as shown in Fig. 6. This circuit delivers up to 4 A with a motor supply of 40 V. High power speed control circuits like this are useful in the industrial and electromedical fields. Another useful feature of the TDA7272 is that a TTL- compatible tacho signal- derived from the commutation pulses-is available on pin 14; there are 6 pulses per rotation. This output can be used, for example, to count the revol- utions for applications such as measuring the flow rate of a pump, or the travel of a ser- vomechanism. The pin 14 tacho output may be connected to a presettable up/down counter, or to a counter/timer periph- eral such as the ...