该帖子说明了使用单个IC 555和其他一些被动组件的简单融合或爆炸的汽车制动灯指示器电路。这个想法是由乔尔·贝根加斯（Joel Bayongasan）先生提出的
Technical Specifications
You innovations are great! Thanks for this blog. May I request something please? I was searching for a circuit that will detect a blown brake lamp.
一辆汽车通常有两个并行连接的汽车。
I am looking for a circuit that would light an led indicator if one of the bulbs is busted. I hope you can help.
Thank you.
该设计
By introducing the above shown circuit between the lamp and the supply, the intended blown brake light bulb indicator can be easily built and implemented in any vehicle.
功能非常简单：
The IC 555 is configured as a simple voltage comparator, where its pin2 becomes the sensing input.
The BC557 along with the associated R1, R2 resistors forms a current to voltage converter stage.
Using Resistor Sensor
就像朗g as a working bulb lamp stays connected across the shown points, a small negative potential corresponding to the bulb current consumption is developed across Rx.
This potential becomes sufficient to keep the BC557 triggered and conducting which in turn keeps pin2 of the IC high.
在上述条件下，IC的PIN3保持较低，LED仍关闭。
但是，在某种程度上，汽车灯泡融合或停止照明，跨RX的电势消失或减少到BC557仅停止进行操作的程度。
这立即使IC高的PIN2呈现，LED开始发光，指示用户向用户吹动制动灯泡情况。
The above design can be also effectively used in many different applications which require some kind of current (amp) monitoring such as an over-current or over-load cut off etc.
R1可以计算如下：
R1 = 0.7/BULB电流等级
The above explained circuit can be much simplified through the following configuration:
Simplified Schematic
Using Reed Relay Switch
The above discussed blown car lamp, broken car lamp indicator circuit can be also implemented using a simple reed relay circuit as explained below:
How the Circuit Works
The里德电路在本文中解释的是，仅组成一个芦苇 - 拉雷，一个LED和一个电阻器。它提供了较便宜的吹灯警报技术。
LED安装在仪表板周围的适当位置，并在相关灯泡故障后立即关闭。使用许多此类电路来跟踪各种灯或一组灯，这显然是可行的。电路（图1）通过将电流通过芦苇 - 拉雷的工作线圈提供给灯的功能。
如果特定的灯熔断器，电流会立即掉落，导致芦苇继电器打开并关闭LED。电线的数量必须在工作线圈上打开，以使其通过灯的标准工作电流有效地关闭芦苇触点，并且仍然足够小，以确保芦苇继电器能够在灯碰巧爆炸时能够打开。
Usually, a reed relay needs around 30 to 100 AT (ampere turns = current x no. of turns). Therefore, considering the reasonably high level of currents utilized by car lamps, within this specific application the coil on the reed may contain just a few turns only. For instance, the two car headlamps pull a current of around. 7.5 A (at 12 V).
因此，具有50条规格的芦苇弹性可能只需要七个转弯即可显示每个大灯的电流。如果两个灯都燃烧，则电流通过芦苇卷轴掉落到一半左右，导致芦苇停用，仪表板导致关闭。
图2中所示的电路是一个替代模型，如果灯需要更换，则可以使LED照明。
This allows a bolder warning specifically at nighttime. Nevertheless the circuit in figure 1 is also failproof.
To make sure that the caution technique works correctly, it's advocated that an independent reed relay is employed to keep track of lamps of varying wattage, i.e. separate reed switches for the back lights, brake lights, headlamps etc.
Additionally it is likely to utilize a solitary relay to screen each right and left turning signals with a double winding around the coil.
Nevertheless, it isn't recommended to make use of one particular relay to monitor a circuit or combined circuits that has in excess of two lamps can be ' turned ON ' at the same time, the circuit of figure 2 is utilized then the supply to the LED must be obtained from the switched part of the lamp supply.
This makes sure that when the relay disconnects out because of the lamp getting powered down the LED doesn't illuminate, because its power is additionally shut off. It is essential to notice that the winding thickness employed to wrap the relay coil must be a minimum of as heavy as that found in the actual car wiring, to reduce the voltage drop over the coil and likely overheating.
刹车轻衰竭监视器电路
Below shown is another blown brake light indicator using the IC NE555 timer. When the two brake lamps are functioning, the lamp LP remains illuminated. However when any one of the lamps or both the brake lights tend to be burn creating an open circuit the lamp LP begins blinking at 2Hz frequency, which is enough to signal the driver regarding a brake light failure.
When both the rear lamps work in a sound condition, the current passing by means of R1 activates TR1 blocking capacitor C from charging, which allows the pins 2 and 6 at the supply potential. In these situations pin 3 of the IC is held low which keeps lamp Lp illuminated. On the other hand if a single or the two lamps become faulty TR does not get switched on, which allows the NE555 IC to oscillates continuously at 2Hz, causing the lamp LP to flash.
谢谢!
好的，先生。谢谢你。
Good day!i am doing this project.My only problem is the led light still remains on when i connect and disconnect it to the lamp.can anyone help me?thanks…
which circuit did you try? you will have to calculate Rx properly and make sure that it develops around 1V across it
I have tried the 1st circuit with ic555 and one more thing is:
1) i have used the L.E.D. brakelights instead of filament bulb for the lamp.
2)my led brakelight is 0.07ampere so i got 10ohms for my r1.
3）如果我想使用细丝灯泡，我应该使用多少瓦灯泡？谢谢。
you can use the bulbs which are normally used in motorcycle break lights, the auto spare part shopkeeper will be able to guide you correctly
我看到了……先生，还有一件事，这是该电路中只有一个灯泡吗？谢谢。
a motorcycle break-light will have only one lamp so yes only one bulb is shown here…
Hi! Great tutorial!
How about if the bulb would be power up by 220v in AC? Which modifications I have to do? Thank you so much!
谢谢，可以通过用光耦合器，桥梁整流器和传感电阻代替感应电阻和相关的晶体管来完成。
Could you explain the calculation of the R1 resistor, is that R1=0.7 divided by bulb wattage, ie a 5 watt tail lamp, equals 0.14 ohm.
R1 = 0.7 / BULB电流
If I want add this bulb light indicator in my car(12v) ,how I do this circuit on the vehicle.
你好。
很棒的文章。我将提到芦苇继电器方法，因为我在很多年前使用过的几辆汽车都使用了芦苇继电器方法。但是我看到你救了我麻烦。
I got a reed relay from Tandy (MANY years ago, 40+!) and simply wound the brake light wire that came with the car, around a 2 inch reed switch. There was a section of wiring that had enough slack to allow me to do this. When I pressed the brake, the current through the wire was sufficient to energise the reed switch.And I didn’t need to make sure my wire was thick enough, and because the wire was standard to the car, the voltage to the brake light was the same as standard.
这是一个额外的优势是，可以将芦苇开关放置在仪表板附近的仪表板下方（或刹车灯电线所在的任何地方），因此无需将长电线运到刹车灯/S（或任何地方）。
我也用这个校长当我设计一个成矿t a drag racing timing system. I installed a reed switch with a few turns of 240 volt wiring warpped around it (one in each dragstrip lane) to sense when the cars reached the finish line. A simple 240Volt sensor and finish light was installed at the finish line (one for each lane, with seperate actives). So when the cars finished, the finish light came on, drawing current through the reed switch winding, energising the reed switch. This was fed into the timing system to measure ET.
Hi, thanks, yes I agree reed switches are indeed very handy for quickly implementing small projects like the above. Appreciate your valuable feedback.