Hello,
I am building a small one shot timer circuit for a friend. The circuit is to control the glow plugs on a deisel motor.
The plan was to use a one shot monostable multivibrator which would kick in when the key is turned on and provide a 12 v pulse to a mosfet for 10 sec.
After which it would turn off and stay off.
Simple enough using a 555 so I built a few circuits in Multisim. I quickly learned however that the 555 needs a low pulse to trigger the action, thinking simply I
Built an astable multivibrator to connect to the trigger pin using transistors. It oscillates at a frequency of about 7hz.
I'm having an issue however as multisim
a) Keeps crashing while simulating.
b) shows a constant voltage at the 555 output of about 6v.
Therefore I'm unable to test the operation of this circuit or if I'm even on the right track. Can anyone confirm that an oscillator can be used to trigger a monostable multivibrator or is it required to be a quick negative pulse and return to vss?
Can anyone shed some light on why Multisim hates this circuit?
Here is the Multisim schematic.
A few notes worthy of mention.
This is just the basic controller circuit, the glowplugs will certainly be connected to a mosfet or relay etc capable of handling the huge current they need.
My friend also wants a potentiometer which will replace the 90k resistor and an override which will be a simple button which will allow the glow plugs to stay on while the button is pressed etc.
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