wiring and diagram

The AC mains line that we get in our household electric socket outlets, may at times be full of dangerous fluctuations. These may either be in the form of a sudden high voltage or a low voltage. Both the situations can be very “fatal” to our sophisticated electronic equipments like TVs, DVD players, refrigerators, computers etc to name a few.

A simple electronic part such as an LED can play an important role in displaying the condition of this AC mains voltage and warn us of a possible electrical hazard.

Yeah, we will exactly learn how to make ac voltage indicator from led through a construction of a little electronic circuit.

You will need the following mentioned parts for the project:

TRANSISTORS T1, 2, 3, 4, 5 = BC547

ZENER DIODE Z1----Z5 = 3 VOLTS / 400mW

RESISTORS R 1—R10 = 1 K ¼ WATT, CFR.

CAPACITOR C1 = 1000uF/25v,

DIODE D1 = 1N4007

LED 1, 2, 3, 4, 5 = RED 5mm DIFFUSED

PRESET P1, 2, 3, 4, 5 = 47K LINEAR

GENERAL PURPOSE BOARD = 6” BY 2”

TRANSFORMER = O – 6 VOLTS/ 500mA

  It is completed through the following few easy steps:

 In the procured general purpose board, with the help of the circuit schematic start inserting the transistors first in a straight line and solder their leads.

Similarly insert and solder the resistors, zener diodes, LEDs, capacitors, presets etc. in an organized manner and solder them with reference to the circuit diagram.

The following testing details will furthermore help you to understand exactly how to make ac voltage indicator from led:

For testing the completed circuit board you will require a transformer with multiple voltage outputs.

Connect the transformer to the AC mains; also connect the common secondary output of the transformer to the negative point of the circuit.

Make an alligator clip/ wire assembly. Solder the wire end of the clip to 1N4007 diode input.

Now bite the clip to the 3 volt output of the transformer, adjust P1 so that the first LED just starts glowing.

As above go on connecting the clip to 6, 7.5, 9 and 12 volts of the transformer and adjust the presets P2, P3, P4 andP5 so that the relevant LEDs just start to glow at the respective voltages.

This completes the testing and the setting of the circuit.

Finally join the 6 volt transformer to the circuit and switch ON the power. You will find that LED 1, 2 and 3 are glowing brightly, LED no.4 is glowing with less brightness while the last LED is completely OFF, indicating a safe level of AC mains voltage.

Now in case the voltage exceeds a high level (above 260 volts) the last LED will start glowing brightly indicating a dangerous situation.

If the voltage drops to a dangerous level (below 160 V) LED 3 and may be LED 2 may cease to glow, again indicating a bad low voltage.

It’s a simple home fun project that will cost you hardly anything, yet the result will truly amuse you. Build a simple LED flasher and find ways to use it for decoration.

There you must have studied how a transistor can be used to switch a load connected to its collector through a small voltage applied to its base. The circuit of a simple LED wig wag flasher presented here incorporates just a couple of transistor and is wired as a multivibrator. The transistors alternately switch the LEDs connected to their collector points to produce an attractive flashing effect of LEDs. The circuit may also be used as an LED emergency flasher unit.

You will require the following very few numbers of components to build this circuit:

Resistors ¼ watt, CFR, 5%

R1 and R2 = 22 K,

Potentiometers = 47 K,

LED series resistors are all = 150 Ohms,

LED RANDOM COLORED 5mm = 40 nos.

Capacitors Electrolytic Radial

C1 and C2 = 10 µF / 25 Volts,

Transistors, General purpose

T2 and T2 = BC 547 B

General Purpose Board = Small piece 4” by 4”

 The construction of this LED flasher is very simple and is finished through the following simple steps:

In the given general purpose board, begin by inserting the two transistors somewhere around the centre of the board. Keep at least an inch of space in between them.

Solder and cut of their leads cleanly.

Next fill the board with the resistors and the capacitors. As above solder and cut their leads with the help of a nipper.

Now go on interconnecting their soldered leads as shown in the circuit diagram.

The entire procedure should take not more than ½ an hour. This concludes the circuit board assembly.

Take a suitable plastic enclosure, drill appropriate holes for the potentiometers on its front panel.

Fix the potentiometers into these holes and connect them to the relevant points of the circuit board with the help of flexible wires as per the circuit schematic.

To complete the LED string wiring just go through the following points:

In one of my previously written articles you can find a detailed discussion regarding the method of connecting the LEDs in series and then in parallel.

Just follow the circuit description of the article and complete the construction of two LED strings.

Or alternatively you may just do it as per the wiring diagram of the LED connections in this article itself.

Ultimately you will find that there are two negative points coming out of the two LED strings and a common positive.

With the help of the given LED wig wag flasher schematic you may proceed the testing of the unit in the following manner:

Connect by soldering the LED string outputs to the appropriate points of the circuit board.

Finally connect a 12 supply to the completed circuit assembly, instantly the whole of the LED string will start flashing displaying a true fairy light effect.

This LED string light may be positioned appropriately over the wind shield of your car for a nice little decoration.

The potentiometer controls may be optimized as per your taste to get more amazing results from the circuit.