This is a Simple blown fuse alarm circuit for AC line. It causes we know immediately when broken fuse circuit and it has a few components so easy to build and very cheap.
Fuse Electronic devices that are important to prevent damage to the circuit. When a short circuit occurs, but sometimes we have to fret because the fuse is blown.
We have 2 Circuits diagram
First: Blown AC fuse indicator with neon light
But we do not know makes waste time and thought the machine was broken. But truly broken a fuse. We can fix this easily with a fuse circuit in Figure 1.
Suppose firstly our fuse is blown, AC220 volts so flow through way R1, D1. A capacitor-C1 thus charged until voltage up to 80 volts. C1 will discharged out of D2 and R4. When is this the neon lamps so has dropped across glow. But its brightness will has specific period of time, when C1 discharged completely it will not bright because not has voltage to it. But it will work just like the first, doubling again, Thus see as the neon lamps flashing for fuse blow alerts.
The flashing of neon lamp we can control with C1 and R1 as we need to fast flash so reduce value of R1 and C1, but you want slow flash then increase R1 and C1 only. For R4 will acts limit current to flow through the neon lamp not too much.
Around this time the Fuse not blown, then AC 220 volts will flow to R2 instead of R1. Because R1, the resistance is much higher.This is why it makes the neon lamp glow instantly. And because it has a continuous power on all the time. C1 in this time will not be able to charge it. Was excluded because of D2 and R3 only.
How to build this projects
This project is not used many components so can soldered directly connected. No need to use PCB as Figure 2. But must to check all parts correctly capacitors and Diodes and lamp.
Figure 2 the components layout of this projects
The components List
Resistors size ½W +5%
C1: 0.22uF (224) 400V
D1, D2, D3: 1N4007___1000V 1A Diode
AC wire, Neon lamp, Fuse in used,
Note: Below is other circuit that same this circuit above.
In sometimes electronics our circuit Fuse torn already. Must change suddenly with the cause time Fuse we must know immediately. Then have Light Flasher when Fuse Lose circuit help warn you. The Neon lamp will about the light all the time. If Fuse good usual. But when Fuse torn or be damaged it will Flasher immediately by winking rate from note by R1 and C1 be valuable about 10 time per second. Hope that this circuit will advantage with friends ,
Second: AC Fuse indicator using 2 LED
The Fuse failure alarm with 2 led light that LED display when the load is low resistance or short circuit, fuse blow once. LED1,LED2 show fuse state. In circuit use a few parts.
How it works
This circuit will show the performance of the equipment,or Check the fuse in the circuit.The circuit is small and the power supply voltage of all kinds.
It display with LED, 2-color in one. Which is cathode common kind,the anode has two separate terminals.
If the circuit is functioning properly LED, it shown in green colour.
The display is red, when the fuse in the circuit is damaged.The resistor R1 limits the current to flow through the LED is about 2 mA.
This is enough to make the LED light.If it lowers the R1 down, the LED lights up.
In the normal operation of the circuit and The fuse is not damaged. The zener diode to prevent the green and red LED lights up simultaneously.
Zener diode prevents the LED is green and red lights simultaneously.
The high efficiency LED when connected in parallel. The red LED uses high-voltage so that only green LED lights up only.
Diodes D3 and D4 will prevent dangerous for the LED. While the half cycle negative voltage of the alternating current voltage.
However, if the DC supply voltage. I do not have to use diode protection.
How to build this projects
This project uses a few components so can assemble the circuits into the universal PCB board.
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