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For a project I need a zero crossing wave like this

Its generated by an inductive coil of a distributor of a car engine where that signal triggers a CDI (capacity discharge ignition) when it falls from positive to under -0.3v.

My target is to reproduce or at least mime such a zero crossing wave with a PWM wave using an Arduino Nano in a car environment.

In the circuit below I tried this by using a 2N3904 NPN transistor where the -5 volt are provided by an ICL 7660.

But with this circuit it results only in a +1v/-1v PWM (screenshot below) and not in a +5v/-5v PWM … actually a +2.5v/-2.5v PWM would be sufficient.

My question is: how can that circuit above be optimized to get at least a zero crossing +2.5/-2.5v PWM.

Thanks a lot in advance and sorry for the first complicated question attempt. Andrew

For a project I need a zero crossing wave like this

Its generated by an inductive coil of a distributor of a car engine where that signal triggers a CDI (capacity discharge ignition) when it falls from positive to under -0.3v.

My target is to reproduce or at least mime such a zero crossing wave with a PWM wave using an Arduino Nano in a car environment.

In the circuit below I tried this by using a 2N3904 NPN transistor where the -5 volt are provided by an ICL 7660.

But with this circuit it results only in a +1v/-1v PWM (screenshot below) and not in a +5v/-5v PWM … actually a +2.5v/-2.5v PWM would be sufficient.

My question is: how can that circuit above be optimized to get at least a zero crossing +2.5/-2.5v PWM.

Thanks a lot in advance and sorry for the first complicated question attempt.

this is my firt post here and maybe you can help me.

For a project I need a zero crossing pulse wave (PWM), generated with an arduino and an ICL7660.

My approch till now is using a 3904 transistor as below, but I think it shurely needs to be optimzed.

This gives me the following output.

My target is that I want to drive a CDI unit which normally is triggered by an induvtive zero crossing puls signal from an engine distributor – and above this above should "mime" that inductive signal where the CDI gets triggered by.

See below the original distributors output (here only +/-1v would be needed as the CDI needs a pulse signal from positive falling straight down below -0.3v to get triggered.

How the circuit above can be optimized? as that simple 3904 way as I used above shurely is a very poor way.

For a project I need a zero crossing wave like this

Its generated by an inductive coil of a distributor of a car engine where that signal triggers a CDI (capacity discharge ignition) when it falls from positive to under -0.3v.

My target is to reproduce or at least mime such a zero crossing wave with a PWM wave using an Arduino Nano in a car environment.

In the circuit below I tried this by using a 2N3904 NPN transistor where the -5 volt are provided by an ICL 7660.

But with this circuit it results only in a +1v/-1v PWM (screenshot below) and not in a +5v/-5v PWM … actually a +2.5v/-2.5v PWM would be sufficient.

My question is: how can that circuit above be optimized to get at least a zero crossing +2.5/-2.5v PWM.

Thanks a lot in advance and sorry for the first complicated question attempt. Andrew

this is my firt post here and maybe you can help me.

For a project I need a zero crossing pulse wave (PWM), generated with an arduino and an ICL7660.

My approch till now is using a 3904 transistor as below, but I think it shurely needs to be optimzed.

This gives me the following output.

My target is that I want to drive a CDI unit which normally is triggered by an induvtive zero crossing puls signal from an engine distributor – and above this above should "mime" that inductive signal where the CDI gets triggered by.

See below the original distributors output (here only +/-1v would be needed as the CDI needs a pulse signal from positive falling straight down below -0.3v to get triggered.

Thanks a lot for your support! Andrew

this is my firt post here and maybe you can help me.

For a project I need a zero crossing pulse wave (PWM), generated with an arduino and an ICL7660.

My approch till now is using a 3904 transistor as below, but I think it shurely needs to be optimzed.

This gives me the following output.

My target is that I want to drive a CDI unit which normally is triggered by an induvtive zero crossing puls signal from an engine distributor – and above this above should "mime" that inductive signal where the CDI gets triggered by.

See below the original distributors output (here only +/-1v would be needed as the CDI needs a pulse signal from positive falling straight down below -0.3v to get triggered.

How the circuit above can be optimized? as that simple 3904 way as I used above shurely is a very poor way.