3.-Pin Solid-State Car Turn Indicator Flasher Circuit – Transistorized

虽然，大多数汽车电子设备都进化成固体型号，但是转弯指示器闪光机单元是一个仍然依赖于许多现代汽车中的继电器的设计。

基于继电器的闪光灯的缺点

基于继电器的机电闪光器单元有几个主要缺点：

1）首先，这些是在自然的机械中，通过快速磨损和撕裂，因此往往会很快受损。

2) Secondly, the flashing rate from these electromechanical circuits are load, voltage and temperature dependent. Meaning, the flashing speed can get affected if the ambient temperature is high or if the battery voltage drops, or if the load exceeds a specified limit.

这也意味着如果用户想要一起闪现所有4盏灯，他可能会发现闪光速度太快，而且太慢。

固态闪光灯电路的优点

The 3 pin electronic solid state flasher circuit explained here is virtually free from all of these drawbacks. The repetition rate or the flashing rate from this design is practically independent of the supply voltage, ambient temperature, or the load (number of lamps connected).

The circuit also features a warning switch which seems to be very reliable and handy during emergency, or road accident situations. The switch bypasses the car switch and allows the lamps to run directly through the flasher, enabling all the 4 lamps to flash together, sending an SOS like signal during a nighttime road mishap.

此外，这种设计的规格符合汽车转弯指标的所有现行法定要求。

在本机中设置的40到90次闪烁的重复频率根据建议范围，并且电路的设计是这样的，即当转弯指示器开关供电时，指示灯灯立即开启。

How the Circuit Works

该电路基本上是一种使用几个CMOS和栅极N1和N2构建的易图的多谐振荡器。n3，n4。功率晶体管T1，T2和T3起作用的缓冲级，用于输出该难以操作的高功率指示灯。

每当在C2上切换指示器开关，通过D1和指示灯迅速放电。N1的引脚13转高，其输出变低。因此，栅极N3和N4输出产生高，接通T1，T2和T3并打开指示灯。

The astable is now initiated to switch at around 1 Hz frequency, causing the indicator lamps to blink on and off at the same rate.

When the hazard warning switch, S1, is turned on, the circuit continues to function in just the identical manner except that all 4 indicator lamps now get linked in parallel and they all begin flashing simultaneously.

T3, which is responsible for handling maximum load current, should be installed on over a heatsink.

当采用金属外壳以容纳所提出的3销固态闪光灯电路时，可以用螺钉/螺母和绝缘套件夹紧T3。

通过附接到点A和B的端子的电流（AMP）可以非常大幅度（最多8A）因此，应使用厚的电线用于这些电缆连接。如果原先不包括，应安装正电池供电终端10 A保险丝。

PCB Design

Parts List

Resistors:
R1,R3,R4 = 2M2
r2 = 100 k
R5 = 4K7
R6 = 120欧姆（1瓦）
Capacitors:
C1 =10μ/ 16V
C2 = 1 µ/16 V (tantalum)
C3 = 1 nF
C4 = 220 NF
半导体：
IC1 = 4001（b）
T1 = BC 557，BC 177
T2 = BC 328, BC 327
T3= FT 2955 or TIP 2955
D1 = 1N4148