It is always good practice to verify a circuit before using.

Switching-Mode Power Supplies are the most used circuits nowadays. But there are some difficulties with verifying their circuits: vendors do not publish models for all controllers; a model can be locked to be used with some tool; there may be errors in a model; average models want correct parameters and you need some practice of using them; transient models take a lot of time to get small-signal response and also may have errors.

Let’s try to verify one circuit using my favorite electronics design tool “Circuit Calculator”.

Several years ago we had to solve how to enqueue events with an arbitrary delay, e.g. check a status of a payment 3 hours later, or send notification to a client in 45 minutes. At that point of time, we didn't find suitable libraries to accomplish this task, which didn't require us to spend time on configuration and maintenance. After analysing possible solutions we ended up building our own small library delayed queue in Java language on top of Redis storage engine. In this article I'll explain capabilities of this library, alternatives and problems we solved during creation process.