I was contacted by a Facebook recruiter via LinkedIn InMail. I replied, and we scheduled a phone call. The recruiter also sent me a link to the job posting and a few opencompute.org links.

A few days later, we had the phone call. The recruiter asked me some basic technical questions, such as: "What do you look for in a PCB design review?" and "What is your experience with voltage regulation?"

Later in the call, the recruiter mentioned they would need my resume and that I was to complete a Hardware Practical Test. I agreed.

It took me a few days to get my resume ready, during which the recruiter pinged me to make sure I was still interested. I thought this was a good sign, indicating they wanted to move quickly. After a few days, I sent the resume, and we scheduled the Hardware Practical. The format of the Hardware Practical is that they send it to you via email, and you should reply with a solution within an hour. See the exact monostable circuit question below.

I fully and timely solved the Hardware Practical. I tested my solution in a circuit simulator, documented it, printed it out, and verified that it met the requirements. After sending the solution, I heard nothing from them for a week. This was surprising, as it was likely a question they had sent out many times and should have been able to check quickly. It was not a final hiring decision.

In between, the recruiter called me and asked some more questions, such as how I would troubleshoot a signal integrity issue and what interfaces I was familiar with (DDR, PCIe, SATA, etc.).

I always feel awkward when a recruiter asks me technical questions, especially open-ended ones. Can we really develop a technical discussion there, or do I need to match a pattern that a Facebook Engineer gave to this recruiter?

After a week, I received an email stating I was not a fit. This was surprising, as I was very confident about my Hardware Practical solution. The recruiter did not provide any clue as to why I was not a fit: Was I overqualified? Was my experience not relevant? Was it the Hardware Practical? Something else?

Overall, the experience was negative. I would expect Facebook to be more open, professional, and prompt in its communication with candidates. Also, in my opinion, having the recruiter ask technical questions is not the best approach.

Design a circuit with a 0V to 3.3V step at the input and a negative 1ms pulse at the output.

Input: |----- CIRCUIT Output: -----|__|------

Requirements:

• Pulse width is in the millisecond range.
• Simple and low cost.
• Indicate every component used clearly.
• Find a solution that does not use logic gates, but only uses transistors (minimal number of transistors).
• Draw a time graph of all of the nodes in the circuit that are switching.