For this small circuit or any other reasonably small circuit built on a PCB, what would the process be to have a PCB developed to suit the design? The little research I have done leads me to thinking that the PCB isn't that expensive to have printed but to have the drawing file developed to give the printer can cost a bit.

There are only 21 soldered connections in the circuit, 17 component pins and 4 input and output connector pins. That's a pretty small number, so this should be pretty easy to do on perf board if you already know how to solder. If you really want a pc board, several quick-turn prototype shops have free layout software. I've never used that stuff because I have a pro-level system at work, but they get pretty good reviews. You might start a separate thread asking about them to get more focused responses. There have been other threads regarding free layout packages.

ak

 

Hello All,

I can't believe its been almost 5 years since this thread started and I have still got half of the components in the garage to build the circuit and have been "going to" grab the rest when I get time. O well, life gets busy I guess.

Hoping to do something with this soon and provide some feedback.

 

How come it has been 5 years since it was started in Aug, 1, 2016?

 

Haha, just realised I was looking at the membership date of AnalogKid and not the thread date. That feels like a more realistic time span. I need to get some sleep lol.

 

Oh great. Now I feel old (er) !

ak

 

Reviewing the schematic in post #17 -

To increase the time between interruptions to 1 minute, increase R1 and R3 to 33K.
To maintain the interruption at approx. 0.1 second, move the anode of D1 from Q7 to Q6.

ak

 

Hello all.

Finally got around to buying components, breadboard and jumper wires to build this circuit. I am using “D” on the transistor as a positive supply for a LED and it’s working. How can I check if interruptions are actually taking place? I have sat and watched the led and I can’t see it switch off then on again but it could be happening quicker than I can detect. Any suggestions?

 

If you connect a Voltmeter to pin 15 of the IC you should see the voltage pulsing at about 2 sec intervals. That will at least show the IC oscillator is running.
A headphone in series with a capacitor (say, 100n), connected across the LED, should give an audible click every 30 secs or so.

 

Welcome back!

Add another capacitor in parallel with C1. This will slow the oscillator, increasing both the on time and off time. Another 0.1 uF cap should make the off time enough to notice, especially when not looking directly at the LED (peripheral vision is more sensitive to motion and changes). With 1.0 uF, both the on and off times can be measured with a stopwatch and compared to see if the circuit is functioning correctly.

ak

 

I have connected another capacitor and noticed no change. I also measured the voltage at pin 15 of the IC and is seems to be 0.182vdc stable.

Not sure if this helps but I noticed that disconnecting the power supply from pin 16 of the IC has no effect but disconnecting the ground wire from pin 8 of the IC turns the LED off.

 

Sounds like the oscillator isn't running. Perhaps the CD4060 is dead. Note: that IC is static-sensitive.
Do you have a spare?

 

No, I don’t have a spare. If there is no other way of testing it I’ll buy another and double check the circuit.

 

You can use an oscilloscope to measure the waveform at the output pin of CD4060, if you don't have the oscilloscope then you can use a multimeter setup on AC10V and in series with a 0.1uf to measure the waveform.

 

Hi,

I have just noticed the MOSFET provided by the supplier is IRF9540N, 23A, 100V. I am going to assume this is adequate as the amperage and voltage rating are greater than the specified IRFR9024?

 

So I have replaced the IC and the circuit seems to be working however the LED I am using as a load seems to flash at regular intervals, approximately 0.5 sec on and the same off. Any thoughts?

 

Any thoughts?

 

Period - 30-60 seconds - check.
Off time - "momentary" - ?
Voltage - "slot car" - ?
Peak current - ?

I'm not a big fan of using a 555 for long (tens of seconds) period timing, so I'd go with an oscillator/divider driving an output pulse driver.

IF the system runs on +18 V or less
THEN the circuit is one CD4060 and one P-channel power MOSFET (plus timing and protection components).

ak

I was interested in the complimentary pair astable commonly used in road works beacons, but hardly found anything on them.

The bare oscillator produces narrow spikes that can be lengthened by adding a resistor in series with the timing cap.

A Programmable Unijunction also produces narrow pulses. and you can duplicate it with a cross coupled complimentary pair of transistors - the circuit can be turned upside down with a TO92 style SCR if you want the pulses the other way up.

 

Hi All,

So I have pulled this circuit down and rebuilt it several times. All output pins of the 4060 have even on and off times, just at different frequencies. I have searched the net and can’t find anything about how to have different on and off times with this IC without adding another IC. What am I missing, I am out of ideas.