EK030 Running light 3 LED
Part.no: 41024664
A simple little kit with 3 LEDs that light up in sequence. The LEDs are controlled by a phase shift oscillator, which despite the complicated name is a fairly simple circuit.
The oscillator works by amplifying and phase shifting the small inherent noise present in each transistor at each stage. After the third and final stage, the signal is fed back to the first stage again.
The feedback causes the signal to amplify itself and self-oscillate at a frequency determined by the resistors and capacitors in the circuit. One LED is connected to the collector of each stage in the oscillator.
The kit is suitable as a first soldering exercise or as a demonstration of transistors, self-amplification and oscillators.
- Supply voltage: 3 – 9VDC
- Automatic shutdown time: ~15s
- PCB dimensions: 36 x 28mm
Component list
| RefDes | Value | Qty. | Part.no. | Marking |
|---|---|---|---|---|
| C1, C2, C3 | El.lyt capacitor 100uF | 3 | 40520007 | 100uF |
| D1, D2, D3 | LED 5mm red | 3 | 40307020 | |
| R1, R3, R5 | Resistor 22kohm | 3 | 40811422 | |
| R2, R4, R6 | Resistor 470ohm | 3 | 40811247 | |
| T1, T2, T3 | Transistor NPN BC547 | 3 | 40320001 | BC547C |
Assembly guide
Before starting assembly, check that the circuit board is free from damage and scratches. Verify that you have all the components to be installed by comparing with the component list.
Start by mounting the six resistors, 3x 22 kohm and 3x 470 ohm.
After the resistors are soldered in place and the component leads are trimmed, continue with the three electrolytic capacitors, LEDs and transistors. Note that capacitors, LEDs and transistors must be oriented correctly for the circuit to function. See the markings on the circuit board.
When all components are in the correct position, soldered in place and all component leads are trimmed, it is advisable to do a final inspection of the solder joints.
Make sure there are no short circuits or cold solder joints.
If everything looks ok, simply connect a voltage source to the holes marked + and -. The oscillator should start on its own and sequentially turn off one LED at a time.
Interactive assembly guide ↗
Simulation ↗
Schematic
Drawing
