Electronics > Beginners
Make a strobe which automatically varies between 8-20 Hz with a 555 chip?
not1xor1:
--- Quote from: Buriedcode on February 07, 2019, 12:18:26 am ---Notice the clever trick on the first 555 - the output is fed into the CV pin to change its internal thresholds, this gives a much wider range for upper and lower thresholds. Please don't assume this will work on a breadboard - the model of the NE555 in LTspice is "ideal", in reality the "trig" and "thres" pins are connected to comparators internally, and these may not be able to read voltages too close to VCC or GND. So if you can - prototype it!
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it would probably work better with one of those CMOS spiced 555... even without the opamp buffer
Buriedcode:
--- Quote from: not1xor1 on February 07, 2019, 06:21:26 am ---it would probably work better with one of those CMOS spiced 555... even without the opamp buffer
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Possibly, but even if the resistors in the CMOS version are 100k, it would still pull the first 555 off timing. Not by much though! And if the value of the first 555's resistors are kept low (meaning the cap has to be rather large) it shouldn't make that much of a difference. Good call.
I'm tempted to test this myself now.
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