Fastest Quiz Bell/Alarm

Posted on Feb 4, 2014

This is aquiz bell/alarm circuit. This circuit indicate fastest finger first . This circuit has one bulb for Quiz master and one for each contestant. The bulb will illuminate when a button is pressed. the cathode of the 9v1 zener sees approx mid-rail voltage. The Quiz Master bulb is also illuminated. Here is the circuit: There is no other bulbs

Fastest Quiz Bell/Alarm
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can be lit until the circuit is reset because The zener comes out of conduction and no voltage appears across the 120R resistor. The reset switch must be a normally closed push button, to disconnect the power supply when it`s being pressed. A pair of cross-coupled SCRs can be used to build a first-response monitor circuit, as shown in the schematic diagram below. First-response circuit is popular in quiz application where the first contestant who press the button will prevent the other Continue reading †’. This is a switching circuit that provide latching mechanism to make a set of radio buttons using push buttons. This circuit consist of interlocking circuit that manipulate the signal to latch and release the previous latched section. The circuit latches Continue reading †’. The figure below show us a zener regulator. The essential component is the dropping resistor R which the value given by (V-Vo)/I, where I is the desired output plus 10%. As long as the supply voltage V is constant, the Continue reading †’. This is a little audio amplifier, it is similar to the audio amplifier which is used in small transistor radio. This circuit draws about 30 milliamps from a 9 volt supply. This circuit consist of two stage. First stage is Continue reading †’. WARNING: Don`t touch any part of the circuit when the circuit is running (connected to the powerline), this circuit is not isolated from mains supply. This is transformerless...

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