555 Timer Circuits

Built many a 555 timer circuit back in the day! But in modern times, I can get an ATMega328p already attached to a PC board for $2.50 and load code on it to do whatever I want, including blink a red LED.

Not only are cheap microcontrollers often an easier choice for things the NE555 might be used for, they often draw far less power as well. I personally prefer to use an even smaller and cheaper micro like the ATTiny13A. It's also worth noting that your traditional 555 timers don't like to run below 5V, for that you'll need something like an LMC555. If you're building up a parts inventory, it often makes sense to have a bunch of very cheap micros rather than special purpose parts.

The main advantage of 555 timer is that it is configured with a resistor/capacitor kit. No computer or programming required.

Microcontrollers obviously have more than 1 bit of memory + 2x analog comparators + one 33% / 66% voltage divider (which is all a 555 timer truly is).

What is surprising however is how flexible 1 bit of memory + 2x analog comparators + one 33% / 66% voltage divider

Another way of looking at it is the 555 is useless without multiple extra parts, where as most MCUs can operate with only a bypass cap (and even that is often optional in practice). But you do have to buy a programmer ($5 these days) and get comfortable with firmware, which puts some analog folks off. I'll admit that there is a certain elegance and appeal to using only parts you fully understand and nothing extraneous.

Even if you have a microcontroller, there are simple situations where the 555 can come in handy.

For example, switch debouncer could be solved in code, resistor+capacitor or other methods. But you know what's one of the best performing switch debouncers?

1-bit of memory with an analog comparator. Aka: a 555 Timer.

> 555 is useless without multiple extra parts

Not needed for bistable multi vibrator (aka: just a flip flop mode). Which happens to be the debouncer circuit.