TREE

Nowadays you can buy white LEDs, which emit quite a bit of light. They are so bright that you shouldn’t look directly at them. They are still expensive, but that is bound to change. You can make a very good solid-state pocket torch using a few of these white LEDs. The simplest approach is naturally to use a separate series resistor for each LED, which has an operating voltage of around 3.5 V at 20 mA. Depending on the value of the supply voltage, quite a bit of power will be lost in the resistors. The converter shown here generates a voltage that is high enough to allow ten LEDs to be connected in series. In addition, this converter supplies a constant current instead of a constant voltage. A resistor in series with the LEDs produces a voltage drop that depends on the current through the LEDs. This voltage is compared inside the IC to a 1.25-V reference value, and the current is held constant at 18.4 mA (1.25 V ÷ 68 Ω). The IC used here is one of a series of National Semiconductor ‘sim...

circuit diagram: A total of four 1.2V cells are used here. Resistor R2 limits the charging current. For charging Li-ion battery (used in mobile phones), shift switches S1 and S2 to ‘on’ position and use connector ‘C.’ Regulator IC 7805 (IC2) provides 5V for charging the Li-ion battery. Using this circuit, you can charge a 3.6V Li-ion cell very easily. Resistor R3 limits the charging current. Fig. 2 shows the circuit for a small LED-based lamp. It is simple and low-cost. Six 10mm white LEDs (LED2 through LED7) are used here. Just connect them in parallel and drive directly by a 3.6V DC source. You can use either pencil-type Ni-Cd batteries or rechargeable batteries as the power source. Assemble the circuit on a general-purpose PCB and enclose in a small box. Mount RCA socket on the front panel of the box and wire RCA plug with cable for connecting the battery and LED-based lamp to the charger.

This is a Simple Dome Lamp Dimmer Circuit Diagram . A reading light inside the car greatly assists passengers during night, but often the interior dome lamp is too bright and distracting to the driver. A linear regulator such as a rheostat can be used to control the brightness of the dome lamp but it consumes a lot of power. Here is a dome lamp dimmer that gives you a fairly linear control over the lamp brightness from low to high intensity while consuming little power. Since it is a pulse-width modulated chopper circuit, you can also use it to dim a halogen bulb or control the speed of a mini drill, etc. Simple Dome Lamp Dimmer Circuit Diagram In the circuit, timer NE555 (IC1) is wired as an astable multivibrator to produce square wave at its output pin 3. The output of timer IC1 charges/discharges capacitor C1 via diodes D1 and D2. Adjust pot meter VR1 to control the RC time constant during the charge-discharge cycle and get the timer output with the desired pulse width. Thus the bri...

Valid schematic circuit diagrams of fluorescent lamps with a voltage source using 12 volt battery. This circuit 12 volt fluorescent lamp is very useful if the power goes out or can be used in a dark place with no electricity , but can use  the battery 12V . This 12V fluorescent lamp circuit i have tried and the results are bright , durable until decades. You can use 12Volt fluorescent lamps up to 40W . Use quality 12 Volt fluorescent lamp, do not use the fast heat , because the fast was also damage the transistor at 12Volt fluorescent lamp circuit . Do not occasionally mistaken in putting up the transistor . Description for 12 volt fluorescent lamp Circuit Diagrams : R1 = 220R/0.5W R2 = 1/0.5W C1 = 100n/100V C2 = 220uF/50V Q1 = D1885/D1710 A/B= To A fluorescent lamp/ and B to B fluorescent Lamp and just use one pin B = Battery 12 volt with currents above 5A Roll of copper wire on ferrite rod, with : L1 = 1.2 mm diameter wire with many loops winding 20 times L2 = 1.2mm di...

Fluorescent lamp assembly using only a 3V voltage source. 2 battery which i parallel to supply its circuit of fluorescent lamp . By using the above circuit is very useful if it saves electricity and power outages at home , or used in  a dark place. Circuit of works, and lamp lights This is circuit , battery , and fluorescent lamp 20W Working circuit on the dark

 Emergency Lamp With 555 is a single option representing lighting trendy the route of electrical power outages. With Emergency Lamp Sequence 555 uses a 12VDC voltage source with the aim of can stay provided from your 12V battery. Emergency Lamp 555 Sequence With these incredibly very regular and tranquil to make up as every of the components simply to hand from the souk place. Emergency Lamp Sequence With this special 555 can flip to the light 5W-10W.  Emergency Lamp with 555 Timer The circuit is residential with the astable multivibrator simultaneously with the IC 555 with the intention of is certainly employed to mendrive transformer by way of Q1. intended for specially details is often viewed very well within the sequence Emergency Lamp With 555 follows. Functioning frequency range of 555 Emergency Lamp With this specific arrange of configurations R1, R2 and C2. T1 in sequence Emergency Lamp With 10V 500mA 555 is in fact a transformer. Secondary element (0-10V) is conne...

Nowadays you can buy white LEDs, which emit quite a bit of light. They are so bright that you shouldn’t look directly at them. They are still expensive, but that is bound to change. You can make a very good solid-state pocket torch using a few of these white LEDs. The simplest approach is naturally to use a separate series resistor for each LED, which has an operating voltage of around 3.5 V at 20 mA. Depending on the value of the supply voltage, quite a bit of power will be lost in the resistors. The converter shown here generates a voltage that is high enough to allow ten LEDs to be connected in series. In addition, this converter supplies a constant current instead of a constant voltage. A resistor in series with the LEDs produces a voltage drop that depends on the current through the LEDs. This voltage is compared inside the IC to a 1.25-V reference value, and the current is held constant at 18.4 mA (1.25 V ÷ 68 Ω). The IC used here is one of a series of National Semiconductor ‘sim...

Nowadays you can buy white LEDs, which emit quite a bit of light. They are so bright that you shouldn’t look directly at them. They are still expensive, but that is bound to change. You can make a very good solid-state pocket torch using a few of these white LEDs. The simplest approach is naturally to use a separate series resistor for each LED, which has an operating voltage of around 3.5 V at 20 mA. Depending on the value of the supply voltage, quite a bit of power will be lost in the resistors. The converter shown here generates a voltage that is high enough to allow ten LEDs to be connected in series. In addition, this converter supplies a constant current instead of a constant voltage. A resistor in series with the LEDs produces a voltage drop that depends on the current through the LEDs. This voltage is compared inside the IC to a 1.25-V reference value, and the current is held constant at 18.4 mA (1.25 V ÷ 68 Ω). The IC used here is one of a series of National Semiconductor ‘sim...

This simple emergency lamp circuit uses very components and yet is able to provide some useful service. The shown device is able to switch ON automatically when mains power fails, illuminating all the connected LEDs.As soon as power is restored, the LEDs shut off automatically and the connected starts charging through the built in power supply. The circuit employs a transformerless power supply for initiating the explained automatic actions and also for trickle charging the connected battery. Parts List R1 = 220K, R2 = 10K, D1, D2, D3 = 1N4007, Z1 = 15V 1watt, zener diode, C1 = 105/400V C2 = 100uF/25V T1 = 2N2907, or 8550, or BD 140 Z1 = 12V, 1 watt LEDs = white, high bright type.

This deluxe solar-powered light  uses a battery and solar cells salvaged from a solar lamp with a four-cell battery (4.8 V nominal terminal  voltage). RGB Solar Lamp Circuit Diagram The circuit can operate from any  DC voltage around this value and  its current consumption, at 20 mA,  is low. This means that the battery  can give up to five days of operation. The circuit consists of an Atmel  ATtiny microcontroller which drives  a red, a green and a blue LED directly  from three port pins. Series resistors are of course included to limit  the LED current. The microcontroller  drives the LEDs in sequence to produce an  RGB running light effect. The microcontroller  is also responsible for ensuring that the light automatically switches on when it gets dark  and off when it is light. The light sensor is  made from one of the solar cells from a bro-ken solar lamp (it is more common  for the battery to fail rathe...