CMOS 4060B won't count

Thread Starter

abcinc

Joined Apr 29, 2009
26
Circuit is http://uk.geocities.com/ronj_1217/c4060s.html#2

I have a 360K resistor in place of R3 and R4, C3 is 10uF 16V, R5 is 4.7 meg. Pin 12 (reset not connected but everything else is.

Issue is no oscilations on pins 9, 10 and 11. I have 12.24 volts DC on pin 16 and gnd is connected to pin 8

Pin 9 gets constant 50 mv, pin 10 gets constant 12.24 V and pin 11 gets constant 8V all DC. Any ideas? I checked all connections with DVM and checked the resistor values also with DVM.

Thanks

Dave
 

bertus

Joined Apr 5, 2008
22,266
Hello,

The reset should go to ground.(it will not count if this pin is not connected).
Is C3 a bipolair capacitor (as recomended at the bottom of the picture)?

Greetings,
Bertus
 

Thread Starter

abcinc

Joined Apr 29, 2009
26
Maplin JA75S does not exist any more or at least I could not find anyplace localally or internet to buy one.
 

bertus

Joined Apr 5, 2008
22,266
Hello,

The JA75S does exist at Maplin:

Non-Polarised Electrolytic Capacitors

Description Code Price Status Qty
NP 2.2uF 100V JA78K £0.12 In Stock
NP 3.3uF 100V JA77J £0.12 In Stock
NP 10uF 50V JA75S £0.12 In Stock
NP 47uF 100V
JA72P £0.59 In Stock
NP 100uF 100V
VM76H £0.98 In Stock
NP 220uF 100V
JA71N £2.01 In Stock
Greetings,
Bertus
 
how would the teams feel if they were getting 19:20 instead of 20:00?
You'd be doing very will to get that degree of acuracy. The large value electrolytic capacitor required for a delay of this lengh would have a high tolerance, typically +-20% so at the worst one team might have 16:00 while another might have 24:00.

However I do unserstand that you'll be using the same clock for each team so it probably won't be as bad as this but the drift due to temperature fluctuation and aging of the componants will be significant.

Does anyone have the 555 circuit for minuts? with the value of the capacitor and resistor?
Look at the datasheet, you'll find that T = 1.1RC, study the graphs, rearange the formula for R, then C and plug different values into it until you get the value of T you desire. Having said this you'll need a trimmer pot for adjustment due to the componant tolerances.
 
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