As shown in FIG receiver may help patients avoid missing voice in the daytime, only the receiver itself is working, lights will automatically cut off part. At night the lightin
Click here to download the full size of the above Circuit.
g signal receiver and simultaneously sent with the patients request. Call switch is pressed, and also the primary transformer X1 AC power is turned on, the secondary voltage is rectified, filtered, the output DC voltage by R1 to the VT1 collector. If during the day, due to exposure to light, the photosensitive resistor LDR1 low resistance state, VT1 conduction, its collector is pulled to ground potential, the thyristor BT136 does not work, then only call ringtone can be heard, the lighting signal is inactive. At night, LDR1 due to darkness and high-impedance state, so after pressing S1, VT1 off, the positive DC voltage filtered R1 and R3 may be charged to dawn. VD3 effect allows a constant positive DC bias trigger BT136, so that the incandescent lamp L1 light, so ask at night can hear the bell, but also to see the lighting signal for help. Zener diode ZD1 is used to limit the voltage across C2 is maintained at a stable value set. A, point B on the right side of the circuit section can be replaced at the circuit of Figure, but with the relay to control lighting without thyristors. During the day, due to the low resistance LDR2 bypass the base current to VT2 VT2 end, the relay RL1 is not working. In the evening, LDR2 was almost an open state, the base current through VR1, R4 and R5 flows into the base so that VT1 conduction, RL1 pull bulb L2 light.
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.....
characters left: