Thanks for the nice details. Hi Shubam the you require street light whenever the street becomes dark whether day or night with dark rain carrying clouds, it will become quite dark even during daytime still you require street light. Diode D1 protects the circuit from reverse supply voltage, if the supply is reversed, fuse F1 blows. I know the reason but i don't know how to fix it, fluorescent bulbs have high voltage discharges when its lighten up and that parazite oscilation is affecting the relay coil. One way to reach a reasonable compromise is to initially allow a momentary inrush current to warm the filaments, followed by a series of interrupted short circuits across the lamp that generate the required high voltage to trigger the fluorescent. I also used 2 different op-amps and tested my transistor on another circuit.
The relay would be supplied with its own supply. Figure 5 shows a circuit using the latter option; this circuit also shows how a small amount of hysteresis can be added to the circuit via feedback resistor R5, so that the relay turns on when the light level falls to a particular value, but does not turn off again until the light intensity rises a substantial amount above this value. A 12v zener diode limits the operating voltage of the circuit to 12v. Is this your scheme can be recommended for that? Circuit by David Johnson P. Some types are available in phototransistor form, and use the standard symbol shown in Figure 14 a. Where have I gone wrong? These pulses trigger U2, causing its output to become high and the discharge transistor to turn off. This is a condition where the contacts are making and breaking rapidly — usually at 50 or 60Hz due to mains noise pickup.
If it isnt possible, im okay with that! The automatic lights shall indeed be turned off when the sun start shining the day. As shown, I used a μA741, but almost anything will work. I strongly recommend that any such circuit has at least some hysteresis. Excluding the relay, it would cost about a Euro or less. I havent been able to find any circuit based on this description on the internet and I wanted to know if I could get some pointers.
It could be perfect for example to control your automatic lights. Checking with u, can u pls tell me how to connect a resistor and a led to the relay to test whether the circuit is working or not. Specifications Supply voltage: 12V nominal. I am looking for the cheapest but reliable circuit. Introduction This has very little to do with , but I suppose that you could use it to on your hi-fi instead if a light when it gets dark.
When applied to an electronic circuit, it does much the same thing. Speaking of the light dependent resistor, it will have a high resistance in darkness and low resistance in the presence of light. It is transistor and relay problem or battery not suitable? He wanted this device because his motorcycle was fairly broad and was worried that passing cars wouldnt notice, especially in the dark! The ideal optical sensors for use in the latter applications are the silicon photodiode and the silicon phototransistor. First, if the ldr is 10K to 1M Ohm, would the mid range for the accompanying resistor be 500K ohms? When the switch is in the On position, Q4 and Q3 are off, simulating a dark condition on the CdS cell. Microcontroller MultiChannel Light Dimmer: The project is a microprocessor-controlled multiple channel lighting dimmer, that could be used in theatrical and other applications. Light Activated Switch is a circuit by which we can switch on and off the electrical load appliances like lights, fans, coolers, air conditioners, street lights, etc.
Thus, the Darlington pair gets activated, and then the relay coil gets energized, and thus, turns the load to switch on. No switching system should ever be used without hysteresis, because there will be a point where the relay chatters. You may want to go only with a transistor. The sensitivity of a phototransistor is typically one hundred times greater than that of a photodiode, but its useful maximum operating frequency usually a few hundred kHz is proportionally lower than that of a photodiode. At this condition the voltage at the inverting input will be higher than the reference at non inverting pin and the out put of the comparator will be low ~o V. In case of the street lights erected on highways it is not an easy task to manually control them, but, if uncontrolled, the chances of power wastage would increase.
Hobby Circuit designed by Dave Johnson P. The modification suggested by him is correct. The duration of the sunrise and sunset is easily adjusted and the photoperiod is controlled with a standard24-h Timer. If a normal silicon diode is connected in the reverse-biased circuit of Figure 10, negligible current flows through the diode and zero voltage is developed across R1. It should work, but this is something that you need to test. Also, is the 5-500k ohm the light range or the lowest light and highest dark range? I could get the relay to activate when adjusting the potentiometer. Be very careful with 220.
This is very important, because an unshielded lead will pick up all sorts of noises, so you may need to have much more hysteresis than is desirable. And is it ok to use the Resistor variable linear 100K ohm 0. Photodiode symbol a and alternative ways b and c of using a photodiode as a light-to-voltage converter. When it is completely dark, and up to about 15 percent light, the motor will turn one direction. As you look it with the pin on top,there are 2 pins on one side left and 6 on the other right.
When the light intensity falls below this level, the op-amp output switches to positive saturation and, under this condition, Q1 and the relay are off. If you use a timer for on and off operation of street light whether the sourounding is dark or not the street lights will start glowing waste of electrical energy. Then I checked the value of every resistor again, and all connections. I have build the third circuit and i have change the relay to 6v relay. There are quite a few schematics on the Net that appear quite similar to this, but hysteresis has been omitted — this is a very bad idea, especially if you are driving a relay. The design usually involves a compromise between turn-on voltage and lamp life because the two are inversely related.
As you can see, it is virtually identical. In a simple photodiode, the photosensitivity is greatly increased by using a very thin and thus highly translucent slice of material on the p-type side of the junction, as shown in Figure 12 b ; external light can be applied, via a built-in lens or window, to the opto-sensitive pn junction via this thin slice of p-type material. The first circuit - The blind man's sensor The circuit assembled on a breadboard The circuit is is a simple transistor switch with the base of the transistor connected to a voltage divider. Figures 15 and 16 show typical examples of such circuits, using photodiode sensors. These supplies have another benefit too — their mains power usage is very low — I measured mine at less than 400mW from the mains when all wired up and operational, but with the relay de-energised. Also, the R1 value must, in many applications, be chosen to bring the photosensitive device into its linear operating region. I suggest you get 5 amperes relay.