### Build a Simple Quiz Master Circuit Diagram

How to Build a  Simple Quiz Master Circuit Diagram, Quiz master is a device which uses electronics to decide who pushes their button first, Up to eight players each have their own answer button to press, corresponding to the four Red Team and four Green Team LEDs on the master control board. As soon as the first contestant who thinks that he knows the answer presses the button, a loud tone sounds, all other contestants are locked out, and the contestant`s indicator LED lights on the control board so that it`s obvious who buzzed in first.

The control board also features two selectable time out periods each adjustable from 3 to 15 seconds, setting specified time intervals in which the player must answer before the time`s up! tone sounds. Eight SCRs form the heart of the circuit. The anode of each SCR has a positive (+) bias on it by way of an LED and a negative (-) bias on cach cathode. As soon as a contestant depresses his or her switch button (S4 through Sll), a positive bias is applied to the respective SCR gate.

### Simple Quiz Master Circuit Diagram

That bias latches the contestant`s SCR on, which in turn lights up the appropriate LED on the master control board. At the same time, the activity of the SCR latching on turns on the answer buzzer (BZ) and locks out all other contestants. The lockout occurs because relay K2 contacts operate to remove the availability of a bias voltage to the gate of the other SCRs. The other circuitry consists of a timer circuit and a time`s-up tone-generating circuit.

The timer circuit consists of transistor Ql, capacitor CI, resistors Rl through R3, and trimmer resistors PI and P2, Depending on the adjustment of the trimmer resistors and selection switch S3, a specific time period can be set. The lime`s-up tone-generating circuit is made up of IC1, transistors Q2 and Q3, and the associated resistors and capacitors. The on time of the tone can be set by P3. Relay Kl, which is operated by the timer circuit, serves to reset the entire unit for the next question.

### Build a Low Noise And Drift Composite Amp Circuit Diagram

How to Build a Low Noise And Drift Composite Amp Circuit Diagram. This circuit offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance.
Low Noise And Drift Composite Amp Circuit Diagram

Compared to a standalone FET input operational amplifier, the composite amplifier circuit exhibits a 20-fold improvement in voltage offset and drift. In this circuit arrangement, A1 is a highspeed FET input op amp with a closed-loop gain of 100 (the source impedance was arbitrarily chosen to be 100 kfl). A2 is a Super Beta bipolar input op amp. It has good dc characteristics, biFET-level input bias current, and low noise. A2 monitors the voltage at the input of A1 and injects current to Al`s null pins. This forces A1 to have the input properties of a bipolar amplifier while maintaining its bandwidth and low-input-bias-current noise.

### High Power Output Amplifier TDA7294

The famous SGS-THOMSON ST Microelectronics has introduced a Hi-Fi DMOS high-power amplifier circuit TDA7294, its sound great taste bile, which due to its internal circuit from input to output are field-effect devices, rounded sound Mild, delicate Rounuan.  However, with its assembly amplifier, only TDA7294 single-output power is only 70 W, BTL access law is 100 W from top to bottom, do not feel that power cushion. The author several tests, used to promote TDA7294-level, direct-drive one to four pairs of high-power transistor parallel, the output of strong currents, the power output of 400 W (mono), and the circuit is simple and no need to debug that can reliably work Basically, the IC has maintained a sound and performance.  Ruzuo The figure below shows, R6 for the feedback resistor, the author of the value in debugging 22 k Ω more appropriate, R6 also decided this circuit gain, the gain value will increase.  Quiescent current depends on the power of R7, R8, when its value…

### Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram.To day if we are talking about expert Cell phone Jammers we are conversing about this schematic underneath. First off all you should be very very cautious how to use this apparatus. Its completely illegal and so the reason. I post this Circuit is only for educational and testing causes. This type of apparatus is being utilised by security for VIPS, particularly at their limousines to avoid blasting device initiating while the vehicle passes from the goal cell phone-bomb. Off course there are those who use it to make a antic or to make the persons crazy in the rectangle block you are.
The power of the jammer is currently sufficient to do your thing, but certainly you can place a 30W linear power amp at the RF output and impede a much wider locality. So, Be pleasant individual with that and recall that there are people who may need desperately to obtain or make a call and one of them could be you! And if you can't oppose of functioning …