Why the output of ICs doesnt reach 5V??

I connect a +9V supply and ground to 555 timer, the output is merely 0.6 Vpp. I connect the output of 555 to a comparator LM293, with ground reference, the output is still less than 1Vpp. I doubt the comparator couldnt cope with frequency 40kHz, hence i replaced it with op amp LM385. The waveform is nicer, no distortion, however, its Vpp is still less than 1Vpp.

When i increase the supply voltage from +9V to +12V, the output of 555 timer, op amp, just increase slightly to less than 1.5Vpp.

hmm.. i wonder why?

What are you using to measure? What is the frequency and pulse width of the 555?

Scope?

Since you mentioned that you measured the output originally as 0.6v p-p, I assume that you're using an oscilloscope. Perhaps the output voltage is fine and you are using a 10X attenuator probe which you've forgotten to include in figuring the input sensitivity of your scope. If on the 0.1v/div range with a 10X probe, the screen will actually be 1v/div, so a six-division-high waveform will be 6 v p-p, not 0.6 v p-p.

Dean

If you are using batteries, they may be runing out of current.(flat battery).