| 摘要 |
The first NAND gate(G1), when the high signal of TTL level is delivered to one input terminal from the voltage converter(12), as the other input terminal is low, outputs high. The second NAND gate(G2), working as a inverter, outputs low. At the same time the first and the second diodes charges the capacitor(c). And when capacitor's charging timing is determined, the oscillating frequency can be determined, and as the capacitor repeats charging and discharging and as an input of the first NAND gate(G1) is converted high and low, and thus the rectangular wave with a designated frequency can be produced as the output of the second NAND gate(G2).
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