555 timer monostable operation


http://www.play-hookey.com/digital/555/timer_555_sequencer.html Wanted to make input, B,C (displayed in attached picture.) Input will be arduino SPI 1MHZ(planning) And before make it I run program at orcad. But result is terrible.

https://drive.google.com/open?id=1nK8vRjXyOO-qD9PNqi9xHznCRF-oIuwy https://drive.google.com/open?id=1JmRAbRI-zXnwJ7CHR_QRR4dnfFaLDNp9 have a file at dsn file.


I don't understand why middle voltagemeter is getting long pulse(looking C3 R3, it will be 0.5*1*1.1u) and didn't know why it get 200ns period between red graph and pink graph.

Also yellow(last one) have to be 0.5n*1k*1.1=0.55us but 0.7us.

Why my circuit program didn't work?

Hello Dongjee33,
Do you have the required resistors
between +V and pins #2? The
trigger input must be pulled high
so the coupling capacitor can
pull pin 2 low to start the
timing operation reliably.

https://drive.google.com/open?id=1HJjI4tbJXVRfSjJlBHkkOwLkpl9kbgz7 I replace it like it but getting strange graph.

And I know that output rise time is 100n and fall time is 100n so I understand the purple graph is 0.7us not a 0.5us.

But at Now on, I couldn't understand why red one is 1.5us not a 0.7us.

Hi, You need a pull-up resistor on pin 2 of X1.