### RL and RC Time Constants.

Recall that in our lamp and cap circuit, the lamp lights up for a second, but then goes out. What determines how long the lamp stays light? The lamp is not a perfect device which generates light from electricity. It has losses, and shows electrical friction (read: resistance). Any time that you have a resistor and a capacitor in a circuit, we call it an RC circuit. Likewise, if there is a resistor and a coil in a circuit, we call it an RL circuit.

In this circuit, the moment the battery is applied, current starts to flow through the resistor, and a voltage begins to build up across the plates of the capacitor. The amount of time that it takes for the voltage across the capacitor plates to reach the voltage of the battery, is a result of the values of the capacitor and the resistor. The larger these two values are, the longer it will take for the entire voltage to appear across the cap. This relationship is expressed by a formula, and is called "Time Constant". The formula is:

T = RC

where T= Time in seconds, R=resistance in ohms, and C=capacitance in farads.

A time constant also exists between coils and resistors, however, because of the nature of how a coil is made (it is essentially a piece of wire), time constants in RL circuits are much smaller. Recall that earlier in the course, we discussed that inductors and capacitors are almost exact opposites. Here is another formula which will seem re-hashed.
T = L / R

where T= Time in seconds, R=resistance in ohms, and L=inductance in henries.

Remember this formula?
XL = 2pfL

Well, you are going to have to start using XL and XC again. Because we are going to begin using capacitors and coils in the same circuit. Now the real fun of electronics begins.

### 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 Î© 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 …