Category: Holidays

Here’s what I’ve been talking about over the recent blog entries: The Clipping Stage!

Disclaimer: It’s still not complete; there’s supposed to be an additional capacitor and diode, but we’re testing the resistors and transistor first.

R1 is the Green Resistor, with a value of 510kΩ. It’s connected to the power source (9V) and the collector of the NPN transistor.

R2 is the Red Resistor, with a value of 1MΩ. It’s connected to the base of the NPN transistor and ground.

And we have the emitter of the NPN transistor, leading straight to ground.

The issue: V3 doesn’t have any voltage going through. We think that it’s either A) the transistor’s fault, or B) the breadboard itself, which might have short-circuited. Either way, it’s bothersome, and progress has been slow during the holidays.

Anyhow, I’ll have to get it done by this year, since I’ll be busy with my exams in the next. Oh boy.

2N3904, you will be missed.

Moving on. I just re-tested the stage from yesterday.

I should REALLY learn how to read the bands. My big brain couldn’t differentiate these resistors:

Going from left to right: R2 and R1. They’re used for the schematic below:

Everything but V3 worked today. Apparently, there’s supposed to be some sort of voltage read there. I got absolutely zilch.

It’s OK. I’ll be trying again soon!

Here’s my circuit now, for future ref. I might need to move some parts around, because it’s totally not working at the moment.

I spent three and a half hours testing the “clipping” stage of the circuit. There was no current on the oscilloscope at first — turns out we’d used the wrong resistor. I should probably learn to read resistor bands.

Plus, the transistor was funky. Even after we’d identified the collector, base, and emitter.

Thankfully, we found out why. NPN transistors only work at a certain voltage, at 0.7V. Our resistor resisted too much of it, and left 0.3-0.4V. Which was quite odd, since the schematic specifically called for a 510k Ω resistor.