Electronics is Fun

We've been talking about transistors recently, particularly the BJT, on What Can You Do With Two Transistors? Part 1 to 3. And  perhaps before we continue with more installments on the topic, more discussion about the transistor as an amplifier would be very helpful. These tiny devices have been a game changer since they were introduced more than 50 years ago, and still don't fail to mesmerize people. From amplifiers, band gap references, current sources, to trans-linear amplifiers, they are absolutely phenomenal devices with a host of utility. We would dwell on the concept and  idea of the amplification on this blog, perhaps not the same as many of us have been taught about transistors in school. The concept we will be discussing here is equally applicable to the MOSFETs. Many of us were taught that the BJT gets its amplification property from its Beta, the ratio of the collector  current to  its base current, and that it mainly is a current amplifier because of...

This is a continuation of a running series on the kinds of simple circuits we can do with basically just  two transistors. In Part 1 we talked about Current source and Multi-vibrator, and in Part 2 we discussed Linear Regulators. We will continue with more practical circuits that can be very useful in many applications. There are instances that we would like to translate a digital logic voltage from one level to another, say from 5V to 3V, or vice-versa. The input perhaps coming from a circuit that has a higher logic level that needs to input to a different logic level. For a single direction of signal, a single transistor would be enough. Bidirectional functionality can be achieved using two transistors, Bidirectional Logic Translator , as shown below. R1 serves as a pull-up resistor to 5V in the circuit. The input typically comes from an open-drain or open-collector output, pulled up to supply by R1. The enable pin should be tied to the lower of the two supplies. Whe...

In the first installment of this series, we talked about what exciting things we can do with just two transistors, in particular BJT transistors. Some of us might probably think that we don't talk a lot about BJT transistors nowadays, not with the thrill, excitement, and trend brought about by high advancements in the technology in the Internet of Things, Machine Learning, Machine Intelligence, Advanced Algorithm, etc.. But we argue that these little circuits and components are constantly in the background of the advancements we see around us and we should not ignore them, as much we will not ignore what we currently enjoy and what the future holds for us. Let's continue to look at the Two-Transistor Series Regulator we talked about in Part 1 . The circuit below is a different version, now using the transistor to provide feedback from the output. This makes the output voltage higher. The output is still derived from the zener voltage. The output voltage is now a s...