Apologies if this is a bit simple, but I'm new to this!

How do I set the speed for a 4060B chip? I want it to trigger every 5 minutes (fairly accurately).

I've looked at the instructions here: http://www.reuk.co.uk/Timer-Circuits-With-4060B.htm and it looks like I need to trigger on pin 4. However, I don't get how I set the resistors and capacitor.


2 Answers 2


According to the datasheet the formula for the R/C oscillator is:

\$ {\dfrac{1}{2.3 \cdot R1\cdot Cx}} \$

So for R1 = 10k\$ \Omega \$ and Cx = 10\$\mu F \$

\$ {\dfrac {1}{2.3 \cdot 10k \Omega\cdot 10 \mu F}} = 4.34Hz \$

You can use any of the Q4 to Q14 pins for output, they have different division ratios of the oscillator speed.

Where Osc = the oscillator frequency the frequency of each Q pin is Q4 = Osc / 16, Q5 = Osc / 32, Q6 = Osc / 64 and so on up to Q14 = Osc / 16384.

So with the above example Q4 will toggle every \$ {\dfrac{1}{4.34Hz}} \cdot 16 = 3.68\$ seconds

For five minutes you simply need to choose a compatible frequency and divider ratio. 5 * 60 = 300 seconds. If we choose the divider as Q6 then 300/64 = 4.68 seconds needed for the oscillator.

A quick shuffle of some figures gives one possible way as R1 = 204k\$\Omega\$ and Cx as 10\$\mu\$F. This would give:

\$ 64 \cdot \left( \dfrac{1} {{\dfrac{1}{2.3 \cdot 204k\Omega \cdot 10\mu F} }}\right) = 64 \cdot 2.3 \cdot 204k\Omega \cdot 10\mu F = 300.288\$ seconds.

Pretty close. I would probably use a smaller more precise capacitor and a larger resistor for more accurate timing. For best accuracy use the crystal option.

  • \$\begingroup\$ With such a long divider chain available you can use a faster oscillator and a bigger divide ratio. If your oscillator operates at say 10 to 100 hz the components are usually much more manageable that if you need somewhere around 1 HZ BUT do what works best for you in practice. | Do not use an elecrolytic for timing or a cap that is badly temoerature affected. eg most ceramics are poor. Use a quality resistor. (Most are these days. Most.) \$\endgroup\$
    – Russell McMahon
    Nov 17, 2011 at 18:15

You said fairly accurately. So I wouldn't use an RC oscillator but a crystsal oscillator. The 4060 can also be operated as crytstal oscillator.

A 32.768kHz (clock) crystal would yield a 2 Hz signal (after all 14 stages of the 4060). So you need another divider/counter, e.g. a 4040 to count 5 * 60 * 2 = 600 pulses at 2 Hz.

You can use half a 74HC21 (4 input AND gate) or a simple wired-AND gate to detect the terminal count (600 = 512 + 64 + 16 + 8 = 2^9 + 2^6 + 2^4 + 2^3).

Or probably cheaper and more flexible with just one IC: use a small crystal clocked microcontroller.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.