The reference chosen is an LM329 sub-surface (or buried) zener (ZD1). Whilst the circuit symbol is that of a zener, it`s actually an active device, which results in much lower dynamic impedance than a normal zener, of around 1ohm. It also has low noise relative to it`s output voltage (6. 95V nom. ), due to the sub-surface zener reference. Other devi
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ces can be used, depending upon desired output voltage / noise performance. This Zener is biased through a resistor (R5). Note though that the bias voltage is from the regulator +ve sense point, or output, which is the quietest +ve rail of the system. Biasing the device in this manner means that the reference is well isolated from the effects of noise at the regulator input, in effect benefiting from a super-reg to itself! The output of the reference is then filtered, via a simple RC network (R7 / C4). The resistor values are chosen so that the error amplifier (IC2 or IC3) inputs see a low, and matched source impedance of 500 Ohms, thereby facilitating optimum DC stability and dynamic performance and minimising EMC susceptibility. C4 is a very high performance, low E. S. R. device in order to maximise the filtering effect from the low impedances used. The low impedances bring benefits in terms of reducing the inherent noise of the resistors (Johnson noise) and reducing the effects of EMC / EMI on the circuit. D3 and D4 provide protection against excess differential mode voltage at the op-amp inputs. They are not strictly necessary for the AD797 op-amp, and can be left out for some very minor performance improvement, since the AD797 incorporates these diodes internally. This not the case for many other op-amps though. The reference voltage at the input of the op-amp is compared to a proportion of the output voltage, via the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
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In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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