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Calpe 2 hours ago
In the BOM list supplied by Elektor it indicates C1-C4 with Farnell order no. 1236687. Under this order no. 1236687 is actually a Non-Polarised Electrolytic Capacitor, 2.2 µF, 100 V, MCNP Series, ± 20%, Radial Leaded, 6.3 mm. On page 22 of Preamplifier 2012 (3) C1-C4 are listed as 2.2uF, 100V. Clearly a big difference!
Preamplifier 2012 (1) - introduction and line-in/tone/volume board (110650)
jean pierre gauthier
jean pierre gauthier 4 hours ago
Hello I am interested in your system to measure the temperatures at various levels in my little greenhouse 20M² could you if you play me provide the layout of the card to be made under any format (pdf, eagle, proteus or other )thank you very much
Multichannel Temperature logger [120637]
Winston Ojenge
Winston Ojenge 19 hours ago
If you can test the sensor, counter and GSM module for me, price is not a problem. I am willing to purchase. If it is not enclosed, i can still buy it. But i need all the modules, from sensor to GSM, well tested. Then name your price. Please reply
Industrial Counter for Print Count with Wireless Acknowledgement System [130557]
Patrick Baumann
Patrick Baumann 1 day ago
So, I've started my own D-Watt project. It will be a Stereo-Vollverstärker, which means that it will consist of a pre-amplifier (taken from Elektor's PreAmp 2012) and the D-Watt with less power (only one power supply with lowered voltage) giving roughly 2 x 100 W at 8 ohms. This project page is in German: Let's rumble, - Patrick
200W Class-D Audio Power Amplifier [150115]
cvdo 1 day ago
Today I tried a totally different approach, with an LCD display, which, I hope, in the end to merge with the oscilloscope plan. I have attached a new schematic and a new picture of the result. This time on a 100x48 LCD display. The new setup uses: An LCD display 100 pixels wide, 48 high. This comes from my junk pile and I have used it before so I know how it works. Its disadvantage is that it uses an 8 bit wide parallel input, plus two control wires. So maybe it's better to replace it by a modern colour TFT display with a SPI interface. Any ideas anyone which TFT display to use? Digital to Analog Converter MCP4902. This DAC has two analog outputs and a SPI interface, which saves an enormous amount of pins on the microcontroller. The SPI interface is superfast at 10MHz. An ATMEGA328 in stead of the ATMEGA32. But I think maybe I will revert to the ATMEGA32, because the ATMEGA328 has so few pins and already 10 of the pins are used by the LCD display. I use the ADC inputs of the microcontroller to measure kathode current via R5 and R6. L1/C5/C6 are necessary for good performance of the ADC. Just one NE5532 op-amp. I found out that both the anode circuit and the gate circuit can be done with just one op-amp. IC4A is combined with a couple of transistors to amplify VoutA (of the DAC) to the high voltage needed on the op-amp. It multiplies VoutA by 40. Maximum is 40*5V=200V. IC4B amplifies VoutB by factor -5. Maximum is -5*5V= -25V. Because pin 5 is connected to the cathode (with resistor divider R7/R8), the cathode voltage is automatically added to the gate voltage. I have added D1/D2 as a protection, so that the gate voltage can never be (too) positive. On the photograph I am testing one of the triodes of an ECC85. Four graphs are drawn. The top one is for Vg=0V, the Vg=-1V, -2V and -3V. On the horizontal axis: Vanode, max is 150V. On the vertical axis: Ikathode, maximum is 6mA. What's the conclusion? The original idea, with the oscilloscope looked much better than this cheap LCD stuff. However, I can easily modify the current setup to draw other graphs (Ikathode vs. Vg). Maybe I should make the best of both worlds. Add a second DAC that sends synthesized results to an oscilloscope...
Vacuum Tube Curve Tracer: remake of Tektronix 570