**Please note that as of May 2020 international airfreight has effectively ceased from Australia and so I will only be taking domestic orders until this situation has resolved.

If you are overseas and wish to register an interest please contact me and I will let you know when the freight situation resolves.

Until then please stay safe everyone.**

I was looking for a variable square wave generator and modified a design I found on youtube. One consideration for the timer was that it produced a large range of frequencies from ~1Hz to ~500kHz. I used this cool site to calculate the values of resistors and capacitors. You can read about the design and production process on my blog.

The design incorporates some SMD as well as some through-hole components because I think that is great for learning soldering. The updated design includes extra VCC and GND pins so power can serve both the timer and your project alongside the signal output (from ~5-16V). Also the potentiometer is a multi-turn precision version to allow greater control over the final frequency. A 100nF decoupling capacitor has been added across VCC and GND for added stability. Also the PCB has been rearranged to suit my needs and to be a little more compact.

Assembly Required. Each kit includes:

• 1xPCB
• 1xNE555 timer
• 4x2kΩ 1206 SMD resistors (R1, R2 and LEDs)
• 2xLEDs 1206 SMD (power and signal)
• 1206 SMD Capacitors (2x10nF, 2x100nF, 1x1uF)
• Header pins and selector
• 1x500kΩ potentiometer
• 4xM2 spacers and nuts

Each kit comes in a ziplock bag ready for soldering, then just power on and enjoy the generator.