At the time, I wanted to build The Ultimate Continuity Tester, and I established a wish list of all the features I required: A real continuity tester. Too many multimeters and sounders react at resistances as high as hundreds or even thousands of ohms, which makes them practically us
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eless in many cases. Within a board or a system, there are always medium-conductivity paths everywhere, so they sound most of the time. A connector, a PCB track, or a wire, even a long one, has a resistance generally below 1. Having a threshold much higher than that generates false alarms. Speed. Many testers require a contact of tens of milliseconds or more, which makes the testing of large numbers of connections very frustrating. It is impossible to swipe quickly across a large number of pins. Cheap to make and use. That meant a very small number of dirt-cheap components and a power consumption as frugal as possible from a cheap power source. This ruled out the usual 9-V battery, one of the least efficient and most expensive sources available. No power switch. You invariably forget it`s on the afternoon preceding your holiday leave, and timers aren`t good enough. They tend to go off unnoticed just when you reach the wanted connection. At first sight, the circuit in Figure 1 doesn`t seem very impressive, but it fulfills all of these requirements, and then some. It looks like some half-cooked multivibrator, but appearances can be deceptive. Q1 and Q2 form a two-stage, non-inverting amplifier, whose input and output are connected via C3 in order to cause oscillations. Each stage has its gain carefully defined: Q1 by the ratio of R4 to R1, and Q2 by the ratio of R2 to the sum of R8 and whatever sits between the test probes....
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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