One of the most common electronics starter projects is the Simple Blinking / Flashing LED Circuit. You can find references to this project and diagrams on many websites. I have created a simple BOM (Bill of Materials) that you can get here at Digi-Key to build this circuit. Below is a simple schematic I have built using Digi-Key’s Scheme-it tool. (Values calculated using a 9VDC power supply or battery.)
|PNP Transistors||PN2907A-APCT-ND||Qty 2|
|Resistor 300 Ohms||300QBK-ND||Qty 2|
|Resistor 100k Ohms||100KQBK-ND||Qty 2|
|Cap 10 uF||732-8820-1-ND||Qty 2|
Here is a Cart that has the above components in it for your convience.
Some notes for this circuit.
- Changing the Capacitor Values will change the speed at which the LEDs blink.
- If you change the LEDs in this circuit you will need to calculate the value of R2 & R3.