555 timing
555 timing
(OP)
HEY!!
I am designing a circuit that reads the output from a device and when the output drops below a specified value, I am to output a pulse from a 555 timer chip. The problem is that a 555 timer operates from the positive edge of a pulse and the output from the voltage comparitor will send out a negative pulse as the voltage at the input drops below the reference voltage.
Neo11





RE: 555 timing
<nbucska@pcperipherals.com>
RE: 555 timing
RE: 555 timing
RE: 555 timing
put a inverter to your circuit 7404
RE: 555 timing
RE: 555 timing
the signal source R is small enough for the Ib not to cause
significant error and the amplitude is limited, so it will not blow the transistor.
NEO11 uses a comparator -- why not just switch the inverting and non-inverting inputs ?
<nbucska@pcperipherals.com>
RE: 555 timing
RE: 555 timing
Configure your 555timer ic power supply with a common ground. Say like + or - 5Vdc for 10Vdc supply voltage to the timer so that you can achieve a +5V or -5V voltage swing near saturation.