Please help me identify what this circuit board is designed to do

KLillie

Joined May 31, 2014
137
Maybe the transistors are being used like UJT's to act like alternating relaxation oscillators. The base is not being used?
 

MrChips

Joined Oct 2, 2009
24,402
The two sides of the board have nothing to do with each other.

On one side is a two transistor astable multivibrator. This is not a joule thief.
That circuit could possible run for a long time until the 9V battery drops below 3V.

The other side is possible a soldering practice board.
 

GopherT

Joined Nov 23, 2012
8,012
It doesn't look like there are any copper traces connecting components on the back side of the board where the IC socket is located (left side of board in image below). It is definitely a solder practice board.

 

Thread Starter

Rolland B. Heiss

Joined Feb 4, 2015
236
That's the Blinky circuit widely used for kids' projects. The 3 resistor version makes good sense but I think that 4 are often used to make it a little easier for the kids to understand?
I guess it is just a Blinky circuit of some kind wayneh. The cool thing is that it has now been two weeks and still going strong on that 'dead' 9V battery! It could be that I'm easily amused but be that as it may I'm fascinated by it! :)
 

cmartinez

Joined Jan 17, 2007
7,454
I guess it is just a Blinky circuit of some kind wayneh. The cool thing is that it has now been two weeks and still going strong on that 'dead' 9V battery! It could be that I'm easily amused but be that as it may I'm fascinated by it! :)
I remember that a few years back Pink Floyd released a CD that had a blinking red led right in the center of its cardboard box... the think blinked extremely slowly, but it just kept going and going for several years until it gave out... I've often wondered what the internal circuit of that thing looked like.
 
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