standard electronic schematic, black vector lines on white background. left to right signal path: mf52 10k ntc temperature sensor → ne555 schmitt trigger → logic control → s8050 drive for 5v active buzzer. function assignment for 5 pcs ne555: ne555-1 for schmitt trigger, ne555-2 for vco, ne555-3,ne555-4,ne555-5 for logic control. submodule: cd4026 counter decoder with 0.56 inch 1-digit common cathode 7-segment display, lm358 comparator, 50k multi-turn potentiometer, 1n4148 diode. dotted boxes separate each function block, clear 5v and gnd marks, neat wires, standard schematic symbols, engineering drawing