dual led flasher

Here is your circuit with just corrected component values. That is the only changes made. It is very difficult to extract a good schematic from a picture. http://everycircuit.com/circuit/6540230793101312

Here is your circuit organized a bit to make it easier to troubleshoot. http://everycircuit.com/circuit/4842958837514240 _ _ _The Example section might show better circuits to learn how the App works.

In EC you cannot control the polarity of capacitors but don’t worry as the simulator will assign polarity as necessary.

Robert, well the circuit the first circuit that wyoelk has provided has the capacitors reversed from my effort and have yet to work out how he managed to do it, there seems little difference in the two circuits but am still looking. I figured that everycircuit did it automagically as every time I turned the damn thing around it reversed the polarity on me. Thank you for replying

wyolelk Thank you very much, both circuits work a treat.

So have changed the resistor values to those in wyoleks circuit and the capacitors reversed themselves and it now works. Interesting the values that I provided orginally are those on the actual device and that works fine. So now to sit and scratch my head for a bit.

You’re welcome. He didn’t ‘do it’ he simply drew a more correct circuit:-)

In case anyone is interested the led flasher was from ebay DIY-Kit-5MM-LED-Simple-Flash-Light-Simple-flash-Circuit-Production- the values for resistors on the circuit board are 33k Ω next to capacitor 510Ω next to led

Have now changed the resistor values back to their original val and circuit still works. I also noted that the circuit with revised values from provided by wyoelk had "stalled" at some point, opened one of the switches and closed the switch and it ran again, I am not sure that my original circuit might not have been broken rather needed a jolt of some sort to organise the capacitors into the correct rotation. fun fun fun

Just for kicks for you. Here is a 555 timer chip blinking two leds. _ _ _http://everycircuit.com/circuit/6453605530599424

neat, thanks. I purchased my little flasher to practice soldering as my soldering is abysmal and having put the first one together the damn thing didn't flash, both leds came on. Then I built the circuit in here, and the above is history. Another bizare twist is having restarted my first circuit board a number of times both leds would come on. After the above conversations I powered up that first circuit board and it WORKED, so I turned the power off and on a few times and I couldn't get it not to work. My guess is that because the circuit has two identical parts, it can start in a state where they are balanced and a restart causes some inbalance and then the sides bounce back and forth doing there flashy thing. As I am writing this the circuit to the left has both leds on and nothing much happening. Flick open and close one of the switches and its flashing again. cheers

Malcolm, in the real world resistors and capacitors aren’t “perfectly” matched creating just enough imbalance to allow it to start oscillating. In this app you can trigger this by shaking your phone or injecting some noise into the circuit. Seems that flipping a switch causes a similar effect.

I don't think that polarity matters here as the current is very low.

Molar , fatcat2 , thanks

There are a couple of things people tend to forget. 1. For EC to display what a circuit would appear to be doing in real life, the oscilloscope screen should be set to a 1 second rate. 2. Most people do not adjust the gain of EC's simulated transistors to match the gain of the transistors being being used in real life. 3. EC does not simulate the fact that a transistors gain changes depending on the amount of current flowing through them. 4. It is easier to get these types of circuits to oscillate in EC if the base current is just a little greater than the collector current divided by the transistors forward gain. 5. Normally the base resistor is chosen to achieve the above result. In this case when the components are nominateded a similar result can be achieved by adjusting the gain of the transistor, check out the accompanying circuit. http://everycircuit.com/circuit/6190574552743936

Thanks Billy, usual to flag up from time to time as new users join EC.

@Robert, the formula to obtain the base resistor is collector resistor X approximately 95% the transistors gain, I've messed up when trying to calculate using current.

Real time simulation is more real in multisim.

Thanks I do appreciate the explanations. Billy T your circuit is as far as I can see identical to Wyolek accept for the orientation of the two capacitors and diff resistor values. I don't fully comprehend the explanation re oscillation yet but I have written in down in my notes and will work on it. So each circuit that has been suggested works, ,mine Wyolek and Billy T, interestingly my circuit, poorly laid out as it is, simulates the actually physical circuit the bestl, as I said in an earlier comment I built this circuit because I could not get my physical circuit to flash, now after some bumping on both the physical (restarts) and every circuit (open and close switch) they both worked with original resistor values. My main concern was that I could not get the capacitor orientated, and have since found that once the circuit is bumped the orientation sorts itself out.

You mean cap polarity?

yes originally when I stuck the caps in the polarity was wrong so I removed the links used the widget that rotates the cap hooked em back up and they were still wrong, I tried all sorts of things to get those caps to change opening and closing a switch in the power circuit seems to have fixed the orienttion

Find the direction in which the current is the least. You can set the capacitor polarity accordingly.

When I made a class a audio amplifier, I tried putting the capacitor in either direction, which works just fine since the input current is too less.

Malcolm, I changed the gain of the transistors make bias resistors correct.

thnx

It works. If you want to change the polarity of a capacitor, change the polarity of the thingamajigs connected to either side of it. Simple. A non-polarized capacitor's polarity is automatic. Wait. This is weird. The capacitors contain +- polarity whereas the two terminals are -+.

So what's yr point? Sorry, I didn't understand.