This is a simple current transformer AC load LED Indicator circuit. The LED will show AC current of load, that use the transformer and LED as based on the circuit.
Sometimes we need to detect the large AC current. One way is to connect the LED with the resistors and the diode 1N4001 networks. But its disadvantage is the voltage will drop across them too much.
But the best way is using the current transformer. The advantage of this way is current that will check, can convert to a neat instrument. And, the transformer also helps to separate the current to be measured with a meter out.
Which are very useful in measuring high current or high voltage.
This transformer may use a normal transformer. Using the lower voltage coil connects to the high current. Then, the primary coil connects to the LED or the meter.
In choosing the transformer.
The maximum current of the secondary coil and a maximum current of the LED is determined as follows.
Example: The current detector is 0.6A. Thus the lower coil will tolerate this current size. Assuming that the maximum current for the measurement is 30 mA. So, should choose a transformer 220 volts is 12 volts. To get an accurate conversion ratio (600/30).
The voltage loss to drop across the coil of the transformer is very low. And leakage current across the coil of the transformer is very low and may abandon it.
Thus the voltage loss so as the LED voltage divided by the ratio of the transformer.
The secondary coil of the transformer has to connect to load at all times. So we have the four diodes as the bridge to show both positive and negative waveform. If no load the secondary coil will be normal coil.
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