Design & Technology Resources
©2011 E.Clarvis
Voltage on Trigger input
(pin 2)
Output voltage
(pin 3)
The amount of time that the output is switched on once the circuit has been triggered is dependent on the values of:

R and C

In an exam you may be asked to calculate the time delay generated by a monostable.

You will be given the formula in your exam paper but you must know how to use it. You must always show your working out and always use the units. The formula is...

For example:

If C is 230uF and R is 15600 R and

T ≈ R x C

T ≈ 15600  x  230x10-6

T ≈ 3.588 Seconds
T ≈ R x C
Monostable Multivibrators
Calculating the Time Delay
Remember to show your workings
and use the correct units for full marks.