When the bell push is pressed, the HT12E encoder converts the button press into a coded serial stream that modulates the 433MHz transmitter. The receiver demodulates the signal, the HT12D decoder validates the address, and the NPN transistor drives the doorbell speaker.
Read the decisions behind it.
Separate 3V battery domains for transmitter and receiver eliminate wiring between the pushbutton and the bell, and prevent ground loops.
A base resistor R1 limits current from the decoder output into Q1, protecting the decoder while ensuring saturation.
Using generic ICs with explicitly declared pin roles makes the encoder/decoder and RF module connections readable without hiding RF details.
Reuse this netlist when modelling low-power RF alert or remote doorbell systems where a momentary switch must trigger an audible output through a coded wireless link.