EK029 Decision-maker 2LED
Part.no: 41024638
EK029 is an electronic "heads or tails" game, or decision-maker, that will answer YES or NO.
The circuit is built around two transistors, wired as an astable multivibrator or oscillator. The transistors will start to oscillate quickly when the push button is pressed. When the button is released, the transistors are disconnected from the power supply and is kept running briefly using the voltage stored in the capacitor C3.
When the capacitor discharges through the two resistors R4 and R7, the oscillator will slow down and finally come to a stop with either T1 high and T2 low or vice versa.
The kit is easy to assemble with few components. Suitable for beginners.
- Supply voltage: 5 - 15VDC
- Dimensions: 42 x 32mm
Component list
| RefDes | Value | Qty. | Part.no. | Marking |
|---|---|---|---|---|
| C1, C2 | El.lyt capacitor 2.2uF | 2 | 40520012 | 2.2uF |
| C3 | El.lyt capacitor 470uF | 1 | 40520019 | 470uF |
| D1, D2 | LED 5mm red | 2 | 40307020 | |
| R1, R2, R5, R6 | Resistor 1kohm | 4 | 40811310 | |
| R3, R4, R7, R8 | Resistor 10kohm | 4 | 40811410 | |
| SW1 | Push button 6mm | 1 | 41001412 | |
| T1, T2 | Transistor NPN BC547 | 2 | 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.
The easiest approach is to start by mounting the resistors. The kit contains two different resistor values, 1 kohm and 10 kohm. Compare the color markings on the resistors with the image above or the component list.
When the resistors are soldered in place, continue with the push button. After the resistors and push button, the remaining components can be mounted in any order.
To get LEDs and capacitors to sit straight, start by soldering one lead and adjust before soldering the second lead.
Note that LEDs and capacitors must be mounted in the correct orientation for the circuit to function. Compare with the markings on the board.
Do a final check to make sure all components are in the correct position, oriented correctly and that all solder joints look good.
If everything is ok, a voltage source between 5 and 15V can be connected to the holes marked + and -.
Interactive assembly guide ↗
Schematic
Drawing
