Converting square wave voltages
Converting square wave voltages
(OP)
I am trying to take a square wave with a low of 1.5 VDC and a high of 9 VDC and convert it to a wave from 0 to 12 VDC. Right now I am attempting to use 1/2 of an LM393 comparator. I have a reference voltage of 2.5 volts on the inverting input and my signal on non-inverting input. The comparator output never changes and I end up with a steady 12VDC on my output. I have tried switching the inputs and changing the reference voltage to no avail what are some other suggestions?





RE: Converting square wave voltages
TTFN
RE: Converting square wave voltages
This circuit can also be used to square-up a slowly rising/falling signal and to introduce hysteresis - hey! I've just invented a Schmitt trigger!
Use the CMOS 556 in order to save having to use decoupling capacitors on the Control Voltage pins and don't forget to connect both Reset pins to 12V
If you need a circuit diagram, I can do one for you (but not now - it's 1:00am UK time and I'm going to bed!)
Hope this is useful,
Dave
RE: Converting square wave voltages
Even if you get this to work, however, remember that using the part in this fashion is very likely to lead to chatter on the output unless your input is very clean and monotonic. If there is any noise around the switching threshold the 393 will pass it right through. That's why usually these sorts of comparators have hysteresis features added in to reduce sensitivity to noisy input signals.
RE: Converting square wave voltages
You have a pull-up resistor in 393 output? The 393 is open colector.
M3