EK034 Police Light LED Flasher
Part.no: 41024242
LED blinker with red and blue LEDs that flash in a pattern resembling the light signals of american police cars.
The blinking pattern is controlled by a decade counter whose outputs are activated sequentially and connected with diodes to form an OR gate. The combined output is a quick, flashing sequence of blue and red light.
The clock input of the decade counter is driven by a simple 555 timer with adjustable frequency. To increase the driving capability of the decade counter, the LEDs are connected via individual NPN transistors, each capable of sinking up to 200mA of current per color.
- Supply voltage: 9 – 15VDC
- Current draw: 80mA max
- Dimensions: 96 x 32mm
- Mounting holes: c-c 32mm, ø2.5mm
Component list
| RefDes | Value | Qty. | Part.no. | Marking |
|---|---|---|---|---|
| C1 | El.lyt capacitor 47uF | 1 | 40520024 | 47uF |
| C2 | El.lyt capacitor 10uF | 1 | 41017674 | 10uF |
| C3, C4, C5 | Ceramic capacitor 100nF | 3 | 41015538 | 104 |
| D1 - D6 | Diode 1N4148 | 6 | 40310010 | |
| R1, R2, R3, R4 | Resistor 330ohm | 4 | 40811233 | |
| R5, R7, R12, R13 | Resistor 4.7kohm | 4 | 40811347 | |
| R6, R14 | Resistor 100kohm | 2 | 40811510 | |
| R8, R9, R10, R11 | Resistor 270ohm | 4 | 40811227 | |
| T1, T2 | Transistor NPN BC547 | 2 | 40320001 | BC547C |
| U1 | Decade counter 4017B | 1 | 40360038 | CD4017BE |
| U2 | Timer 555 | 1 | 40350001 | NE555P |
| VR1 | Trimmer pot 100k | 1 | 41018882 | 104 |
Assembly guide
Before you begin mounting components, make sure the board is free from damage and scratches. Make sure all the components are included and are of correct value. Compare with the component list!
Begin mounting the lowest components and work your way up to the largest. IC sockets, resistors, ceramic capacitors and diodes go first. Electrolytic capacitors, connectors and potentiometers go last. Some components are polarized and must be mounted in the right way. Please observe the markings on the board!
The LEDs can be mounted on either side of the board even though the silkscreen is only marked on the backside!
Interactive assembly guide ↗
Simulation ↗
Schematic
Drawing
