"Welcome" circuit a

In front of the shopping mall, the voice of "Welcome" is often heard to express welcome to customers. And use it to attract business. Do you know its circuit
?
    Currently, there are two popular chips on the market, produced by two manufacturers with the same content and different structural forms. The introduction is as follows:
    (1) KD -5603 "Welcome" chip The circuit composed of the KD-5603 chip and peripheral components is shown in Figure 19 -la shown. They have the following common
characteristics:
    ① wide power supply voltage range; ② low power consumption; ③ few external components, some 1C has built-in RC oscillation} ④ language capacity 1.5-4s; ⑤ DC
or pulse trigger; ⑥ output connected to NPN transistor driven speaker ; ⑦ Suitable for using photoresistor as light control IC.
    (2) DY-68 "Welcome" chip The circuit composed of DY-68 chip and peripheral components is shown in Figure c. It has the same function as KD -5603 chip, but the manufacturer is different.