Showing posts with label ac. Show all posts
Showing posts with label ac. Show all posts
Thursday, March 14, 2013
How to Make an LED AC Voltage Indicator Project Do it Yourself
A simple construction and accurate result are the main features of this tiny circuit. Learn how to make ac voltage indicator from led in a most simple and easy to understand method.
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.
Parts Required
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
How to Construct the LED AC Voltage Indicator
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.
How to Test the Circuit?
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.
Tuesday, March 12, 2013
How to Make a Non Contact AC Mains Phase Detector – Measure AC Field Strength Wirelessly
The circuit discussed in this article is of a non-contact mains AC field detector which displays the presence of a mains AC field from a distance of more an 6 inches. The circuit can be used for locating faults in house wiring without the need of making physical contact with the inner conductor of the wire and becomes useful in locating the breaks in a wire by pin pointing the area where the AC mains may be blocked due to a breakage.
The circuit is basically high gain non inverting amplifier which is configured using a few opamps and a few other inexpensive passive electronic components.
Just a couple of opamps have been incorporated here from the IC 324 for the required operations.
Looking at the figure we notice the following things:
The non-inverting input of the IC is grounded making the sensitivity of the configuration to the maximum.
Similarly a feed back loop created by connecting the output of the opamps to the inverting input helps to increase the gain of the set up many folds.
The input is applied to the inverting input 2 of the IC through a blocking capacitor.
The signals entering via the antenna is quickly picked up by the opamp inverting input and sent to the preceding circuit for the required processing and amplification.
It may be interesting to note that the sensitivity of the design can be simply varied by changing the value of the feedback resistor R1, for maximum sensiticity this resistor can be omitted.
However this can make the circuit a bit unstable and might provide false results.
The next stage includes another identical amplifier which is just the repetition of the previous input stage. This stage has been included in order to make the response of the circuit instant and so that the circuit is able to pick even the slightest of RF or the AC field within a certain range.
In case the circuit is intended to be used for detecting mains phase only at touching proximities, the sensitivity may be reduced to the required levels or the second stage may be excluded from the design.
The LED connected at the output is used for displaying the presence of the AC field; an illuminated LED identifies the presence of the field while no light from it provides the opposite conclusion.
By connecting a 1V FSD moving coil meter at the output, the device can be used to detect and measure the average strength of the AC mains present in that particular vicinity.
Parts List
R1 = 2M2,
R2 = 100K,
R3 = 1K,
C1 = 0.01uF
A1, A2 = IC 324
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