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Friday, June 14, 2013

FM Transmitter using a single transistor!

Intro: (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. This contrasts with amplitude modulation, in which the amplitude of the carrier wave varies, while the frequency remains constant. wikipedia

Many thanks to Richard McWhorter (AllAmericanFiveRadio) for the idea and circuit diagram.

In my setup I biased the transistor in a different way. I used 3.5 volts to power the circuit. 
Here is my modified circuit. It works with 1.5 volts and has an excellent range without an antena.
Please note that the 1uF capacitor and the positive terminal of the 1.5V both are connected to the center of the coil.

Saturday, June 1, 2013

New Tesla coil - First test

My new and bigger tesla coil running at 30V/200mA 
I realized its capable of working as an AM transmitter on multiple frequencies (from 3V) 
and also FM frequency !!

Sunday, March 31, 2013

GY-521 (MPU6050) Accelerometer and Gyro with Arduino and Processing !

A demo of GY-521 breakout board based on the MPU6050 Accelerometer and Gyro 
Chip using Arduino and Processing. I tried using it to make an auto balancing robot, unfortunately my motor shield is damaged and i have to postpone the robot project!

Tuesday, March 5, 2013

Friday, February 22, 2013

mini Exciter! Sparks, CFLs and Bifilar. (Test2)

Still using Exciter configuration but I did change the primary coil and 
the transistor (TIP41 instead of TIP122).
Update: I have killed a couple of transistors in a short time after trying to inject
an audio signal to the base of the transistor. The problem was not overheating
of the transistor but something else !! I guess its the -ve part of the audio
signal damaging the e-b junction, or maybe a current surge! (Any idea !???)

Saturday, February 16, 2013

My first Exciter tesla coil! (Test 1)

In this video I test my first tesla coil in exciter configuration using 9v battery 
and 2x AA batteries (DC Boost converter), I guess I have to work on the pancake coil 
and find a better load to get a wide range!
Note: The length of the secondary is 17cm and the diameter is 3cm and there 
are 700-800 turns of 0.25mm wire (The only wire i have at the moment) 
(By the way, the magic ratio for small coils is 5:1 => 15cm x 3cm)

Friday, February 15, 2013

Saturday, February 9, 2013

Simple DC to AC converter (Inverter)

This is a replication of a circuit i found on the internet! I used a 250V to 17V center tab transformer and 2 x 2N3055 transistors. With a 9 Watt load the input current was around 400mA.

Important notice: This circuit is experimental only. Clearly it's not an efficient way of converting DC to AC. For many good reasons, please don't use it in any real life application!

Friday, February 8, 2013

A simple thermal shutdown function for a simple DC boost converter!

Please note that the values in the circuit diagram are not the best choice but based on components i have in my modest inventory. The voltage divider (thermistor/Resistor) connected to the base of the PNP transistor should be set up to yield a suitable switching frequency (taking in consideration the value of capacitance) and a reasonable thermal behavior ! See my other posts on DC converters to see improvements and variations of the circuit! Have fun and let me know what do you think.

Saturday, February 2, 2013