Bus station prompt circuit

Crystal oscillator 2.5*2.0mm 2520 0.67M~170M OSC can be supplied at any frequency

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As shown in the figure is a 4-bit latch / 4-16 line decoder CD4514, dual J-K flip-flop CD4027, time base circuit NE555, pre-settable 4-bit binary up/down counter CD40193 and music circuit KD-153 The site reminder is composed of light-emitting diodes and music circuits, and is mainly used on buses.

Site prompt circuit

In the circuit, the 555 circuit and R1, R2, and C1 form a pulse generation circuit that is used to provide a working pulse to the counter. After the counter CD40l93 receives the carry pulse, its carry and borrow output outputs a high level, which is inverted to output a low state and transmitted to the disable terminal INH of CD4514, so that the 4-bit binary number is sent to the translation. The coder performs decoding. The high state of the output of the decoder causes the LED to conduct light in the normal phase.