| 摘要 |
The electronic BCD 8421 up/down counter according to the subject matter of the invention is a synchronously driven counter which consists of decades according to Figure 3. To avoid uncertainty, all dual flip flops are shown as dual flip flops. The decades of this BCD 8421 counter are made switchable by the additional circuits (65 to 67) and the additional circuit (68) and the decade carry circuit (71). In the decades of this counter, the line (1) is preactivated via an AND circuit (78) so that the position changes nine-zero and zero-nine can be achieved in the simplest possible manner. If necessary, this up/down counter is constructed in accordance with Figure 4. In Figure 4, the additional circuit (68) has a different configuration. <IMAGE>
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