This is a design circuit for a doorbell. This circuit can produces a sound like bird sound. This circuit controlled by transistor NPN. This is the figure of the circuit. The operation of the circuit is beginning when P1 is of experimental value. Start with 220 Ohms or so and modify to suit your needs. The transistor is a general purpose kind and i
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s not critical, almost any PNP type will work. L1 is a bell-transformer which is usually already present in the house. If you wish, you could use a battery instead of the bell transformer. Just hookup a 9-volt battery (or wall adapter)to points `A` and `B` (A=+) the diode (D1) is to protect the circuit from accidental polarity reversal and is optional, but required as a rectifier for use with the bell transformer. T1 is a General Purpose PNP transistor and probably anything will work. L2 comes out of an old am transistor radio. They look like miniature transformers and are usually colored red or green. You have to fiddle with different transformers as the sound can vary depending on the value. The loudspeaker is a 8 Ohm type and must be larger than 200milli-Watt. I used a 2Watt type, but anything over 0. 2W will do.
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....
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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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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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