What Part of ______________________ Don't You Understand ? - One for mapj1 ?

You may not like it Dave, but even in the perfect world of computer simulation, the astable flip flop does not  require the devices to be imbalanced - it will start on noise - I've never yet built one that does not start, (*) and they are in all sorts of things I have done,

The very first flashing lights for my toy train (with two germanium, transistors and small torch bulbs), a very bad electronic music generator (factory reject BC107s from a magazine advertiser of the late 1970s), the saving grace being it only drove headphones, and a device for measuring light levels on forest floors using more of the BC107's, but with the top cut  off and blooped with clear resin to make photocells in series with the timing resistance) Later as the oscillator to generate the programming voltages for an Eprom programmer (2n709s I think - I was nearly 20 by then)  and many since some professionally, and  with scouts for flashing LEDs and so forth.

And full circle, with my kids, as lights for a toy railway, but with LEDs not filament lamps..



Mike

(* ) you do need HFE >> Rbase/Rload and electrolytic caps need to be low leakage, and RC to be long compared to ft/HFE, so not much faster than audio only.


I grant you that the three and 4 stage ring oscillator versions can be unreliable..

You may not like it Dave, but even in the perfect world of computer simulation, the astable flip flop does not  require the devices to be imbalanced - it will start on noise - I've never yet built one that does not start, (*) and they are in all sorts of things I have done,

The very first flashing lights for my toy train (with two germanium, transistors and small torch bulbs), a very bad electronic music generator (factory reject BC107s from a magazine advertiser of the late 1970s), the saving grace being it only drove headphones, and a device for measuring light levels on forest floors using more of the BC107's, but with the top cut  off and blooped with clear resin to make photocells in series with the timing resistance) Later as the oscillator to generate the programming voltages for an Eprom programmer (2n709s I think - I was nearly 20 by then)  and many since some professionally, and  with scouts for flashing LEDs and so forth.

And full circle, with my kids, as lights for a toy railway, but with LEDs not filament lamps..



Mike

(* ) you do need HFE >> Rbase/Rload and electrolytic caps need to be low leakage, and RC to be long compared to ft/HFE, so not much faster than audio only.


I grant you that the three and 4 stage ring oscillator versions can be unreliable..