One-Shot using 555

A one-shot timer based on the 555. It features: optional voltage regulator, adjustable output, pamp output buffer.

Similar projects worth following
# Overall description
The design is a one-hot circuit based on the 555 timer. I needed it at work for two different uses, so I made it somewhat flexible.

# Power
You may choose to use the LDO from Micrel, or you may choose to drop it and use a 0R resistor instead. In both cases, it is possible to use a diode to protect the circuit form wrong polarity on the input power. The LDO solution offers adjustable output voltage.

# Input
The input is made to be used with a push-button, but I'm sure most of you can figure out other ways to trig the timer. It requires a negative edge.

# Output
The output is attenuated using a potentiometer and some optional resistors. This gives a good control of the output voltage. If very good control of output voltage is required, use of an LDO is recommended. The attenuated pulse is buffered in an unity-gain opamp circuit, and finally, the output signal passes through a resistor and capacitor that can be used as current and/or DC limiting dev


LTspice file if you feel like simulating the circuit (without the regulator). It's made on a Mac, but I believe it should work on any LTspice.

plain - 3.33 kB - 01/27/2021 at 07:48



Bill Of Materials. Most parts have compatible parts from other vendors.

Comma-Separated Values - 1.41 kB - 01/27/2021 at 07:26



Schematic and PCB

Adobe Portable Document Format - 356.50 kB - 01/27/2021 at 07:23


Enjoy this project?



Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates