Hi. Im a newb, trying to build a digital clock. I found a website which gave me a diagram and taught me some stuff :
http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock4.htm
But im having problems. Basically I made a 5 volt square wave with a zener diode (verified with my oscilloscope, which I just got yesterday). But I cant figure out how to transfer the signal to my 7490 counter.
When I put my oscilloscope on both sides of the zener I see a 5 volt square wave. But every time I try to wire it up to the counter, when I put my oscilloscope probe between the counter output on pin 11 and the circuit ground im seeing a 28 volt sin wave like from my transformer without even going threw the zener...
I have 1 transformer lead to a 1k resistor to reverse zener to the other transformer lead. This I verified to be 5 ohm sin wave.
Then I have a divide by 10 decade counter wired up like it says here http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock6.htm
This decade counter has a plus 5 volt dc input from a different powersupply I made, and everything that says ground (from that last link) is connected to the dc output of that 5 volt input.
How do I connect these 2 circuits properly to get the 5 volt square wave into the counter ?
http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock4.htm
But im having problems. Basically I made a 5 volt square wave with a zener diode (verified with my oscilloscope, which I just got yesterday). But I cant figure out how to transfer the signal to my 7490 counter.
When I put my oscilloscope on both sides of the zener I see a 5 volt square wave. But every time I try to wire it up to the counter, when I put my oscilloscope probe between the counter output on pin 11 and the circuit ground im seeing a 28 volt sin wave like from my transformer without even going threw the zener...
I have 1 transformer lead to a 1k resistor to reverse zener to the other transformer lead. This I verified to be 5 ohm sin wave.
Then I have a divide by 10 decade counter wired up like it says here http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock6.htm
This decade counter has a plus 5 volt dc input from a different powersupply I made, and everything that says ground (from that last link) is connected to the dc output of that 5 volt input.
How do I connect these 2 circuits properly to get the 5 volt square wave into the counter ?