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How to indicate overflow of 4017 counter? How to stop counter?
Is it possible to force 4017 to set some "flag" indicating the overflow afrer just one full cycle: E.G. to turn an indicator LED on afrer one full cycle and then keep this LED switched on permanently. The "carry" pin of the 4017 is...
Hi Dick,
It have put the breadboards in the metal candy box shown on the picture above. It does not reduce the noise. Perhaps this kind of box is not sufficient for proper shielding? Also I have tried it in different places (several kilometers away). The result is always the same.
Hello,
I have made 100 nanowatt cw breadboard transmitter on 16mhz "computer" crystal.
The signal is picked up by dc breadboard receiver also based on comuter 16mhz crystal.
I can hear the signal at distances of about tens of meters, but when I am trying bigger distances combined with...
Hello,
I am looking for a good tutorial on radio (and antenna) design. I have a good knowledge of math and physics as weel as basic foundations of electronics.
What would you recommend?
Thanks in advance
Truffaldino
Thanks Audioguru,
Although responce curve of circuit you proposing is somehow different at very low frequencies (-110db vs -140db at 10Hz which does not make real difference), attenuation of noice is much more important!
Truffaldino
- - - Updated - - -
And for low-pass filter: is the...
Sorry Guys,
I have re-simulated the filter.
The curves are identical. It seems that last time I did sometsing wrong with simulator.
It was a false alert.
Sorry again
Truffaldino
Hello,
I simulated biased and unbiased Sallen-Key high-pass filters and got different responce curves.
I will be grateful if someone could point out on my error with biasing.
Please, find attached unbiased (double source V-=-V+) and biased (single source V-=GND) schematics.
Thanks in advance...
Hello,
I have built a 16MHZ receiver on breadbords and can hear 10 nanowatt transmitter at the other end of my appartment. The problem is that I am using 1meter of piece of wire on a wooden stick as an antenna and compensate its capacitance with an rf choke attached to the antenna end. As a...
Thanks Audioguru,
I am using proteus schematics/simulation just to pick up right values of resistors/capacitors. I am using 9v -14v supply on the breadboard.
I also try to disable rest of opamps by grounding (+) input and connecting (-) input with the output (this is a kind of ground "voltage...
Dear Audioguru,
Which opamp do you suggest to use instead?
I have also tried TL082 and LM324 with similar results (I think LM324 and LM158 are in fact the same).
Truffaldino
Thanks Audioguru,
Sorry for wrong circuit on the picture I have posted. This is a drawing mistake. In fact my real connections to opamp (-) is identical to the ones you have proposed in your post. Here I attach a circuit drawn in proteus with simulation results similar to yours.
In this...
Hello,
I have collected a direct conversion receiver on 3 breadboards: the first one contains rf stage, the second one contains opamp audio preamplifier/bandpass filter and the third LM386 audio amp in minimal configuration with gain 20.
The rf part is based on NE612 famous mixer. The...
Thanks E-design,
Indeed I had to read that thread more carefully.
Now I have corrected the circuit as well as inductor/ capacitor values, so that their reactances remain the same while frequency is approximately is 1/3 of 50MHz (i.e. 16Mhz).
Simulation results look nice (see images attached)...
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