The purpose of this prototype unit does away with the need for an oscillator. It offers a mains-derived and fully variable 50 hz AC volts down to millivolts for comparison and to check accuracy, of two or more parallel connected multimeters. Sometimes older instruments of this type are favoured to respond better at low frequencies than higher audi
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o frequencies, which are better suited for measurement by wideband audio millivoltmeters. It is to be called to attention that unless otherwise stated by the manufacturer, both mechanical and digital multimeters display all pure and irregular wave shape inputs including square, triangle, sawtooth and integrator, as readings in Mean or Average Form-factor. Obviously the higher the mains transformer secondary voltage output delivered, the higher the AC switched ranges or auto-ranging which can be measured. The choice of transformer and resistor attenuator values can thus be adapted to suit individual voltage range requirements. Caveat: To comply with Health and Safety, ideally a small adhesive warning sign should be affixed to the box lid to state "Danger Mains Inside". The prototype does not have one displayed as not being available. However in this case a screwdriver is required to open the lid, therefore that situation is in my control and at my risk. AC feeds a multiturn pot VR1 which sets the reduced base voltage and then in series to two tandem-wired 1k lin pots labelled coarse and fine. For convenience of adjustment nearer to the hole in the box lid, VR1 is recommended to be supported on the same tag strip. So to improve the waveform to a more acceptable sinusoidal shape, this can be further low-pass filtered by a single 2. 2 mfd or two 1mfd polyester capacitors wired in parallel across the two pots combination as...
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....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
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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