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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

Very simple 555 fridge door Alarm!


The same circuit as in the previous post. Just replace the thermistor with a LDR!