Mechanical 12 Volt DC automotive relays are used throughout the car audio industry to turn on amplifiers, lock doors, roll ‘up windows, etc. However, there is another way to activate such loads, and that way is to use solid state switches. Why would anyone want to replace a mechanical relay that is so depend able Well, for starters, the coil in
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a typical automotive relay has a DC re sistance of around 83 Ohms. This would yield a current of over 140 mA with a 12 Volt source. Although this 140 mA may not seem like a large amount of current, there are many car audio components, as well as sensitive vehicle accessories, that cannot supply even this much current. And when multiple relays are connected to the same trigger output, the com bined resistance increases the trigger current. Other reasons for seriously re considering the use of mechanical relays would have to include cost, space, installation labor, and the annoying click, click, clicks. The cost of a good quality SPDT automotive 12 Volt relay is typically around $2. 25 each at the dealer level and $6. 00 or more at the retail level. Add to this the cost of the terminal connectors (relays are at least four terminal devices), and the fact that relays take up at least three cubic inches each and you might be interested in at least trying a new method. And now for the new method. Actually transistors have been around for over 40 years and there is really not much of anything that is new about them. It is only their applica tion in car audio installations that might be considered as new. Rather than get into a discussion of how transistors work, what they do, etc. , let`s just jump to one particular application ‘ switching energy on and off. Our choice for a good transistor on / off switch is 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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