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We can make an enhancement to DAC drive fan controllers with the use of an external amplifier that closes the loop around the tachometer. Essentially linear control over the full range of 8 bit DAC codes from 0 to 255 is provided by this enhancement. This only requires a little signal conditioning and a suitable amplifier arrangement since the tachometer is already there. Figure a shows us that the tachometer pulses are conditioned such that all pulse width information is removed (differentiated) and only pulse rate information remains. Fan speed or frequency is represented by this pulses. Than, this pulse is used as the feedback to an integrating motor control amplifier. To provide pulses just shorter than the duration of the shortest tachometer pulse at full fan speed, the time constant of the differentiator is initially set. Usually, this will provide a very little gain. We can increase the gain by decreasing the value of either R2 or C1. We have to set the gain so the fan just achi

A 12 watt audio amplifier operating on a dual symmetrical supply of ± 12 volts. The 741 provides the required gain while the speaker drive is provided by the complementary Darlingtons T1, T2 and T3, T4.The input signals for the darlingtons are derived from the supply current of the 741. Since R6 is connected to the ground, the positive or negative signal currents also pass through R4 or R5. The voltage drop across these resistors serves as the input signal to the transistor pairs. An overall dc negative feedback from the common collector junction of T2 and T4 stabilises the dc conditions of the circuit and keeps the junction point at zero volts. Hence, no coupling capacitor is required for the speaker.  12W Amplifier Circuit Using 741 Op Amp Circuit Diagram PARTS LIST R1 10KΩ R2 4.7KΩ R3 270KΩ R4 1KΩ R5 1KΩ R6 47Ω 1W C1 50 Pf C2 0.01 µF T1 BC178 T2 2N6107 T3 AC108 T4 2N5294 IC LM741 LS1 50W 4Ω

CIRCUIT DIAGRAM OF OP AMP BASED MONOSTABLE MULTIVIBRATOR (741 IC) MONOSTABLE MULTIVIBRATOR USING OP AMP 741 Monostable multivibrator is also called as One Shot Multivibrator. It has a Stable State and a Quasi-Stable State. The circuit remains in stable state until a triggering signal is applied to its input. After getting the triggering signal the output transit from stable to Quasi-stable state and return back after a time period. So a Single Pulse is generated for single Trigger. Consider the instant at which the output Vo=+Vsat. At that time diode D1 damps the Capacitor voltage, Vc at 0.7V. Feedback voltage is +βVsat at Non-Inverting terminal. When the negative trigger is applied, the potential at Non-Inverting terminal becomes less than 0.7v the output switches to -Vsat, which makes the diode more negative than -βVsat. Comparator switches back to +Vsat. The Capacitor C starts charging to +Vsat through R until Vc reaches 0.7v and C becomes damped to 0.7v. The pulse width is given by

The sample and hold circuit , as its name implies, samples an input signal and holds on its last sampled value until the input is sampled again. Figure shows the Circuit Diagram of a SAMPLE AND HOLD Circuit using 741 OP AMP with an E-MOSFET. In this circuit the E-MOSFET works as a switch that is controlled by the sample-and-hold control voltage Vs, and the capacitor C serves as a storage element. Read More.....

11-90 hz Subwoofer Filter Using TL072 Op-Amp The subwoofer clarify ambit allows the accession of subwoofers to an absolute full-range system, alms adjustable low-pass clarification with alternative R6 and R8 addition and mono-summing. The Subwoofer clarify ambit to abolish for abstracted pre amplifier to drive the low abundance complete a lot. In tone, alarm tone, accustomed Can not be done … is a accomplished abysmal low bass sounds like a bass drum, or at a cine circuitous in a low articulation if we can be heard with But to add cabinets and amps. The subwoofer ambit is canyon low abundance with in 11-90 Hz. Switching ability accumulation 12V cut out if they charge to use +-15V. I had change the Capacitor to cut out vocals per the red amphitheater mark.