but no drafting software on the laptop.

What's the reason for that?
(Hate to have you scare small children).

 

Memory management conflict between Win 10 OS and Win XP software.

ak

 

Interesting I have Paint XP installed on my Acer laptop running Win10 with no issues.

 

Here's a simple and very tough Circuit that should do what You want .........
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View attachment 340959
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Thank you! This is a novel approach, replacing the traditional 555 timer with a buck converter.

I have a few questions regarding the provided circuit:

1. Does the potentiometer and capacitor on the right function as an initial timing element? And does the Zener diode provide a path for excess current to flow?

2. Initially, the MOSFET will turn on, grounding the low side of the brake (inductor). This should also drive the FB pin of the LT1074 to near 0V. At this moment, does the high of the brake side remain at the VCC level?

3. Since another inductor is connected in series with the brake, will this introduce any interactions with it? I understand the inductor is part of the buck converter circuit, but I'm curious if the presence of both inductive components might lead to unexpected behavior.

 

1)
Yes, the approximate delay-times are provided.
The Zener Protects the Gate of the FET from over-Voltage damage.

2)
Yes.
On initial "Start-up" both the Buck-Converter, and the FET will be conducting at 100%.
The FET will "turn-Off" relatively smoothly, leaving behind only the Current-Limiting-Resistor.
When the Voltage at the Current-Limiting-Resistor reaches the Threshold-Voltage of
the Buck-Converter, the Buck-Converter will start it's PWM-function,
which will accurately Regulate the Current.

3)
The Inductors will not "interact" with anything noticeable as there are 5-100uF Capacitors between them.
The Buck-Converter operates at a preset Frequency of 100kHz
so keep all connections as short and close together as possible
to prevent broadcasting high-Frequency Noise into other nearby Components.

4)
The provided DigiKey-part-numbers are for a ~5-Amp Load.
If You know what you're doing, You can swap them for lesser-rated parts,
but over-kill is always a good policy.

Select the 5-Pin, version of the LT1074 Chip, You don't want the extra features of the 7-Pin version.
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