Posting this for general edification, as well as entertainment.
Now, the "old regulars" here all know this, but did you know what's actually inside that most venerable of all ICs, the 555 "timer" chip?
It must be, what, an oscillator? and some fancy divide-down circuits? after all, it's a timer, right?
I found this block diagram in an old book (Integrated Circuits for Electronics Technicians, by Edward Pasahow, published 1979 (!):
**broken link removed**
As you can see, there's not a "timer" to be seen here. But it is a damned clever arrangement of other components (two comparators, a resistor ladder, a flip-flop, an inverter and a driver transistor) that can be arranged in myriad ways by the user to perform all sorts of tasks. And that 1/3-2/3 voltage divider: pure genius!
I even saw a complete radio receiver (AM) on the web, made using a single 555. I'll have to find it again.
Now, the "old regulars" here all know this, but did you know what's actually inside that most venerable of all ICs, the 555 "timer" chip?
It must be, what, an oscillator? and some fancy divide-down circuits? after all, it's a timer, right?
I found this block diagram in an old book (Integrated Circuits for Electronics Technicians, by Edward Pasahow, published 1979 (!):
**broken link removed**
As you can see, there's not a "timer" to be seen here. But it is a damned clever arrangement of other components (two comparators, a resistor ladder, a flip-flop, an inverter and a driver transistor) that can be arranged in myriad ways by the user to perform all sorts of tasks. And that 1/3-2/3 voltage divider: pure genius!
I even saw a complete radio receiver (AM) on the web, made using a single 555. I'll have to find it again.