Hello all,
I needed to use a pwm signal to synchronize my data collection in two computers. I used a 555 to generate a PWM signal 50% duty cycle waves at 0.5 Hz. When I checked the output wave on a scope, everything seemed in order! and square waves were stable. However, once I connected the output pin (#3 of 555) to the data acquisition, the output wave was not stable!! It appeared that the output square wave's amplitude being modulated! The frequency is not affected though.
I am sure the load from the data acquistion equipment is causing the change in amplitude. However, using an impedence or a power transistor on the output have not resolved the issue for me!
I would appreciate if someone can help me understand what is really going on! Thanks.
I needed to use a pwm signal to synchronize my data collection in two computers. I used a 555 to generate a PWM signal 50% duty cycle waves at 0.5 Hz. When I checked the output wave on a scope, everything seemed in order! and square waves were stable. However, once I connected the output pin (#3 of 555) to the data acquisition, the output wave was not stable!! It appeared that the output square wave's amplitude being modulated! The frequency is not affected though.
I am sure the load from the data acquistion equipment is causing the change in amplitude. However, using an impedence or a power transistor on the output have not resolved the issue for me!
I would appreciate if someone can help me understand what is really going on! Thanks.