View Single Post
  #1   Report Post  
Posted to sci.electronics.repair
Graham Graham is offline
external usenet poster
 
Posts: 46
Default Monostable made from OR gate and CR network , pulse duration ??

Discreet component monostabe constructed from a ‘TTL’ OR gate ,
resistor and capacitor , Im trying to determine what the pulse width
should be from the timing components, but I don’t see any info on this
configuration. I need to certify the cct is in specification .. Its
fed with a 0 5v step

From a common start point, one line direct to gate (1) input, from
the same common start point, a 220 ohm resistor connected to the
second gate (2) input.

From the junction of the 220 ohm resistor and the second gate input is
connected a 0.0022nF capacitor to ground.

The resistor and capacitor form a cr timing network.

Operation appears to be , the initial 'ON' voltage (5v) is applied
direct to gate (1) , the capacitor to ground delays the voltage
applied to gate (2) charging via the 220 resistor.

When the two inputs are at logic ‘1’ then the ‘OR’ Fnction changes the
gate state .

Im seeing a 650nS pulse , has anyone a formula or a chart that gives
a guide to pulse duration ?