This video gives the basics of the bias point, also called operating or quiescent point, of a bipolar transistor (BJT). For a BJT, there are three operating regions: Cutoff, Active and Saturation
This is a prototype of the forthcoming BPM Generator Eurorack Module.
It’s constituted with:
One Prototyping Board #2, two Protoboard #1, one Generic Board #1 and one Arduino.
The Arduino board plugged underneath the Prototyping Board #2
Closeup.
The chips in the middle.
Easy prototyping with the Prototyping Boards. BPM Generator is on it’s way!
This board is the number 2 in the “Permanent Breadboards” series. This time, the layout is no more a simple direct copy of a classic breadboard: it’s a mix between a stripboard and an Arduino shield!
The Prototyping Boards are designed to offer the same look and feel as classic breadboards, with the ability to solder connexions: yes, you will have to solder 🙂
In other words, you’ll keep your prototype for life time! Continue reading Prototyping Board 2: Arduino shield→
Frequency drift is caused by the two transistors in the exponential converter being at different temperatures and minimised by them being on the same substrate. This is temperature balancing. Temperature compensation with tempco resistors tries to stop the Volts/oct changing by matching the exponential term which is proportional to absolute temperature. At 25 deg C the amount of change for 1 deg is 1/(273 + 25) = 0.33557% or 3355.7ppm. That is where the figure comes from, it is not 3300pmm or 3000ppm or 3500ppm or anything else.
Two LEDs Driver
And this is a nice and simple circuit for driving 2 Leds (or a bi-color one) with one logical level : Hi level will illuminate one Led, low level will illuminate the other Led: Circuit simulation
This is an interesting solution, from http://www.blacet.com/tech.html, to provide protection against reverse connection of power supply as well as overcurrent protection caused by any kind of short circuit:
Power input protection and filtering is highly recommended for all modules! See below.
Module Power Input Protection
PS1 and PS2 are polyfuse resettable fuses available in various mA ratings. A typical module with a 50 mA current draw would use 100mA versions.
A power supply reversal causes the diodes to conduct, creating a short circuit. That condition or a short on the PCB causes the polyfuses to heat up and go into current limiting.
Edit:
Now I tend to simply use series diodes on power rails instead. Polyfuse might take some time to react, and then can cause some stress on your PSU. Besides, their “ON” resistance is not negligible.
Keep in mind that diodes have a dropout voltage when in conducting mode. Anyway, a good design should not use the power rails as voltage reference.
If you want to use avrdude with an AVRISPmkII from Atmel on your Ubuntu 14.04 machine, you need to use sudo. If you don’t, you will receive an “Operation not permitted” message.
