Simple Christmas chaser

Today Free Circuit Diagrams 4U is  going to give you a useful circuit diagram.This circuit is mainly operated by two ICs.One is NE555 and IC 4017.When you  build this circuit use a  PCB.If you use blue colour LEDs it would be so attractive.

Note:-

 # Don't supple over 9V
 # Build this circuit on a PCB

1W LED Driver Circuit Diagram

At present most of people use LED light systems.Because LEDs can save our electricity on the other hand we can see LEDs have good life time.So that most of factories use LEDs  to make light circuits.Today Free Circuit Diagrams 4U is going to give you a simple LED driver circuit diagram.This can give a smooth current to your LED this can drive 1W LED.

Note: 
         # Build this circuit on a PCB

Fluorescent Tube Light Driver Circuit Diagram(10W)

This is very useful circuit for us.Because we can light up 10W Fluorescent lamp by using this circuit diagram.This circuit operates with single transformer.I suppose now you can enjoy this inverter.When you wind the transformer do it carefully because that is the heart of this circuit.

LED FLASHER ( About 1Year )

This is so useful circuit diagram for you Because this circuit can light up an LED about 1 year with 9V battery.Here I have used famous IC HEF 4093.

Versatile emergency lamp.

versatile emergency lamp that can be operated in two modes (flasher and dimmer). The circuit is based on the dual op-amp IC LM358.The dimmer and flasher mode can be selected by using the switch S1.






Notes.

* F1 should be a 2A fuse.
* L1 can be a 12V; 2A incandescent lamp.
* IC1 must be mounted on a holder.
* The circuit can be assembled on a Vero board.
* Use a 12V battery for powering the circuit.
* A heatsink must be fitted on transistor T2.
* S2 can be used as an ON/OFF switch.

automatic-led-emergency-light

This is the circuit diagram of a low cost emergency light based on white LED.The white LED provide very bright light which turns on when the mains supply is not there.The circuit has an automatic charger which stops charging when the battery is fully charged.






The IC LM 317 produces a regulated 7 V for the charging of Battery.Transistor BD 140 drives the out put.Transistor BC 548 and Zener diode controls the charging of the battery.

Tips

It is always better to connect a heat sink with BD 140.Before using the circuit out put of LM317 must be set to 7V by adjusting the potentiometer.

Emergency Light and Alarm

This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. When power supply is restored, the lamp or the alarm is switched-off. A switch provides a "latch-up" function, in order to extend lamp or alarm operation even when power is restored.








Parts:

R1 = 220K
R2 = 470R
R3 = 390R
R4 = 1.5K
R5 = 1R
R6 = 10K
R7 = 330K
R8 = 470R
R9 = 100R
D1 = 1N4007
D2 = 1N4007
D3 = 1N4007
D4 = 1N4007
D5 = 1N4007
D6 = Led
D7 = 1N4148
Q1 = BC547
Q2 = BC327
Q3 = BC547
Q4 = BC547
Q5 = BC327
C1 = 330nF-400V
C2 = 10uF-63V
C3 = 100nF-63V
C4 = 10nF-63V
LP1 = 2.5V-300mA Torch Lamp Bulb
PL1 = Male Mains Plug
SW1 = SPST Switches
SW2 = SPST Switches
SW3 = SPDT Switches
SPKR = 8 Ohms Loudspeaker
B1 = 2.5V Battery (two AA NI-CD rechargeable cells wired in series)




Mains voltage is reduced to about 12V DC at C2's terminals, by means of the reactance of C1 and the diode bridge (D1-D4). This avoids the use of a mains transformer.
Trickle-charging current for the battery B1 is provided by the series resistor R3, D5 and the green LED D6 that also monitors the presence of mains supply and correct battery charging.
Q2 & Q3 form a self-latching pair that start operating when a power outage occurs. In this case, Q1 biasing becomes positive, so this transistor turns on the self latching pair.
If SW3 is set as shown in the circuit diagram, the lamp illuminates via SW2, which is normally closed; if set the other way, a square wave audio frequency generator formed by Q4, Q5 and related components is activated, driving the loudspeaker.
If SW1 is left open, when mains supply is restored the lamp or the alarm continue to operate. They can be disabled by opening the main on-off switch SW2.
If SW1 is closed, restoration of the mains supply terminates lamp or alarm operation, by applying a positive bias to the Base of Q2.









Notes:

* Close SW2 after the circuit is plugged.
* Warning! The circuit is connected to 230Vac mains, then some parts in the circuit board are subjected to lethal potential!. Avoid touching the circuit when plugged and enclose it in a plastic box.