| 摘要 |
PURPOSE:To obtain a delay circuit of unidirectionality with low cost by forming an LPF with a static capacitance of collector-base of a transistor of common collector operation and a base connection resistor. CONSTITUTION:A signal from a signal source 20 is fed to a base of a transistor (TR) 25 via a coupling capacitance 22. Then a signal is fed to a TR 6 from the emitter of a TR 25 via a resistor 4. Since the TR 6 is used as common collector, that is, emitter follower, an equivalent capacitance is formed between the collector and base of the TR 6. The time constant of the LPF comprising the quivalent capacitance and the resistor 4 shows the delay time. The delay time is varied easily by using a variable resistor for the resistor 4. Further, the unidirectional signal transmission is obtained by a low output impedance characteristic by emitter follower constitution of the TR 6.
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