Oscillator Circuit Issue

Thread Starter

Đorđe Jocić

Joined Aug 15, 2019
11
Hello guys, how are you? I have recently started learning about electronics from the "Make: Electronics" book by Charles Platt and using the text books published on this very website. Following circuit is for the oscillator that can be used to produce a beeping sound, or in my particular case, flash an LED in a 1s interval.



It works perfectly on the breadboard but for some reason it failed when I attempted to make it on a single hole PCB board - the LED becomes lit but doesn't flash. Following images are from the said PCB board, and while I don't expect a direct answer (it doesn't work because of this and that) I would very much appreciate a hint - as vague as it is possible.




The last 220μF capacitor was added (but wasn't wired) to dim the LED gradually - hence the 2x 470Ω resistors instead one 1k.

Any suggestion and constructive criticism is also welcomed, thanks in advance!
 

Thread Starter

Đorđe Jocić

Joined Aug 15, 2019
11
Thank you very much for your input! In addition to that, after reviewing the circuit again, I have noticed the transistors were wired incorrectly - E and C respectively. My first derp moment in electronics. :)
 

Audioguru

Joined Dec 20, 2007
11,251
Your schematic shows transistors that do not have the very important part number.
North American 2Nxxxx little transistors have pins that are in the order of EBC.
European BCxxx little transistors have the reverse order as CBE.
Oriental little 2SCxxxx transistors have the collector as the center pin.
 

dl324

Joined Mar 30, 2015
9,576
Welcome to AAC!
I have recently started learning about electronics
If you're serious about learning electronics, you should add component designators on every component and part numbers when appropriate. If you're going to use an NPN transistor to drive the LED, drive it low side instead of high side.

Aside from the connections on the base of the transistors, we prefer to use 90 degree wire bends with no unnecessary jogs. Ground always points down.
 

dl324

Joined Mar 30, 2015
9,576
Any suggestion and constructive criticism is also welcomed
If you do a PCB layout, even if you're going to wire point to point, it can give you a component placement that minimizes wire crossings and allow you to use uninsulated wire for most of the interconnect.

Here's a layout I did for 4 discrete R#S# flip flops. Each flip flop is about the complexity of your oscillator. It's on a board 2.5"x2.7" board:
upload_2019-8-20_12-6-40.png

Component layout showing jumpers:
upload_2019-8-20_12-13-57.png
 
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