Component List Resistance: 10K; R1-R5; 5pcs Resistance: 300 O; R6-R12; 7pcs Resistance: 2K; R13?R14; 2pcs Ceramic chip capacitance: 103; C1; 1pcs Monolithic capacitor: 224; C2; 1pcs Integrated circuit: 74LS175; U1; 1pcs Integrated circuit: CD4012; U2; 1pcs Integrated circuit: CD4011; U3; 1pcs Integrated circuit: CD4511; U4; 1pcs Integrated circuit: NE555; U5; 1pcs IC socket: DIP8; 1pcs IC socket: DIP14; 2pcs IC socket: DIP16; 2pcs Nixie tube: 5611AS; D1; 1pcs Switch: 6 * 6 * 5; S1-S5; 5pcs PCB board: 1 pcs Socket: KF126-2P; J1; 1pcs

The kit can be used for electronic technology basics and skills teaching and training, digital circuit teaching, electronic enthusiasts and beginners use training. The 7-segment nixie tube displays the number that was first pressed. Press the reset switch to enter the next round of preemptive answering. The four-person answering machine has data locking and display functions. In the beginning, the four switches are in the open state. After the answering starts, the switch number that was first pressed is immediately locked, while blocking the input circuit and prohibiting other switches from being pressed. The four-person answering machine is mainly composed of four circuit answering switches, answering latch circuits, encoding circuits, and seven-segment decoding display circuits. Power supply voltage: DC 2.5-3.5V; PCB Board size: 63*46mm/2.48*1.81inches.