Simple 555 LED Blinking (Pulse generator circuit with simulation and PCB)

Electrical circuit

You can mount C1 (SMD for small capacitance) or C2 (THT for big capacitance).
C3 may be 0.01uF (10nF).
Power supply voltage could be 4.5V...16V (for  NE555).

Board

It's 2-layer board with convenient XH2.54-2 connectors and M3 hole for mounting screw.

You can panelize many board in one to save money, when ordering PCB fabrication! How to do this see here: 

Real board:

Frequency calculation

There are many online calculators available:

T(HIGH) = 0.693·(R1 + R2)·C1
T(LOW) = 0.693·R2·C1
f = 1.44/(R1+2·R2)·C1

For my case (C1 = 100 uF):

f = 1.44/(R1+2·R2)·C1 = 1.44/(10000+2·10000)·100·(10^-6) = 0.48 Hz

Simulation

Circuit

Output signal

Soldering

You can use ordinary soldering iron, but for SMD ( Surface-Mounted Device) mounting with solder paste is less time-consuming.

Placing components:

Components placed (not all):

Soldered with heating surface:

Test

If you use R1=R2=10k and C2=100uF you will see blinking:

To watch the output signal I use HS402 STM32 Android:

Unfortunately it has maximum sweep 200 ms:

So, for analyzing low frequency signal over a long period of time I prefer Logic Analyzer:

This is a super-powerfull instrument, that helps observe and record simultaneously many signal:

This instrument give you a chance to measure signals timing. The output pulses frequency is equal to the previously calculated value.

Bill of Materials

More photos

Conclusions