As shown in the LED digital display Responder Used for display, enable team members and the audience can see the answer in the result, a very good transparency. This device is simple, making easy.
How it works: Responder digital display circuit as shown. Digital display integrated circuit CD4511 is a major part of the Responder. This is a BCD-7 segment latch / decoder / driver circuit. 1,2,6,7 pin of its BCD code input. 9 to 15 feet for the display output. LT 3 feet for the test side, when it is "0", the output of all "1." BI 4 feet for the blanking end, when the BI is "0", the output are all "0", the end is "0" when the latch can clear the value. LE 5 feet to allow for the latch side, when this Duanyou "0" ? "1" when, a, b, c, d, e, f, g 7 LE maintain output terminal to "0" when the Canadian BCD code corresponding to the display. 16 feet to positive power supply, 8-pin power supply is negative. IC input and output relationship, see the following truth table.

Select components: integrated circuits for the CD4511 or CC4511, MC14511 and so on. Available 0.5-inch display common cathode LED, model BSR5101C (red) or BSG5101C (green). A transistor such as 9014 or 3DG6 NPN-type transistor. 14 diodes are 1N4148 or 2CP series diodes. All resistors is (1 / 8) W carbon film resistors, 300O to 7, 10kO to 5, 100kO for the two, 2.2kO 1 only. Electrolytic capacitors 47µF/16V. Small button switch 9; a small toggle switch: 6V battery clip one.