John Cooley’s EDA & ASIC Design News. E-Mail Synopsys Users Group.
Aug 302008
- If the waveform on the scope droops then you may need to use a 10X attenuating probe or mode. this attenuator is at the tip of the probe hence better measurement possible, also very high frequency signals may be best transmitted over a 50 ohm impedance matched line to the Oscilloscope. The History of Oscilloscope, Learn more about Oscilloscope from the Innovator of the Scope as a Measuring Instrument here is XYZs of Oscilloscopes.
- Karl Ferdinand Braun – In 1897 he built the first cathode-ray tube…oscilloscope. CRT technology is to this day used by most television sets and computer monitors. The CRT is still called the “Braun tube”.
- Test a NPN transistor, DMM in 200K range. emitter negative probe, collector positive probe, it should show open. while still holding that way press wet finger on base and collector, it may show some reading, then it is ok. for PNP swap probes polarity and do the same thing. the wet finger when pressed applies a base current in uA.
- Testing a Mosfet – Transistor Tester – Testing Transistors – Basic Testing of Semiconductor Devices
- The most common reason of DMM failure is when a person tries to measure 230V AC with a DMM in current or ohms mode, with the probes in the wrong sockets. Use external attenuators and shunts.
- A DMM in diode mode or resistance mode can be used to test IR diodes, take it under 100W lamp and measure, cover the IR diode and measure you will see a response in proper polarity.
- If you put the DMM in 2V mode and measure the voltage across a ordinary LED near a 40W lamp you will see around 200mV. Turn off 40W lamp the mV will fall near 0. Even metal-can transistors with their top ground away will become photo sensors.
- When you measure low voltages or high resistance like 1M with a DMM your body must not be in contact with the probe tips. Body resistance is low in comparison so error in reading or loading of mV from sensor, in sensitive and high impedance ranges.
- Do not use an oscilloscope to measure 230V directly, use a transformer, differential probe or attenuator.
- An oscilloscope 1M probe or a DMM 10M impedance can load circuits with nano-pico amps of bias.
- Red socket and probe for positive and black socket and probe for negative
- Is it oscillating ?…. We cannot say, it could also be DC, you need to see if a Clock is present. use a signal tracer or a DMM freq mode, or AC measurement. or build this solorb.com-elect-logprobe. When you do not have a scope you can build one for the PC.
- Polarity and Zero Cross radio-flier.com-opamps.html see the last circuit it is a polarity indicator, which will tell you to swap the leads. VRS Zero Crossing detector circuit, Zero Crossing Detectors, Comparators, Discover Circuits – Zero Cross.
Testing Tools Resources
Analog Designers created Spice, Analog Design Professionals are adding their experience in many commercial and free spice EDA tools. When you are creating a new demanding design, a working solution is achieved by combining workbench and simulation work. Lab Test Bench and Breadboard testing needs to be done along with analog simulation. Power and mixed signal design too, needs to be verified on board. This is more true for a new design lab or new engineers. Experienced designers will not make many mistakes as design blocks would be in their collections or in their knowledge base. It is this knowledge [Read More ....]
LM335-336 – LM335 is a temp sensor, LM335 . use it for temp for CJC. Temperature Sensors – RTDs and Thermocouples, – Chapter 6: Temperature Measurement. LM336-2.5 is an voltage Reference. recision 2.5V shunt regulator diodes, Applied as a precision 2.5V low voltage reference for digital voltmeters, power supplies or in opamp signal conditioning. Current Loop – 4-20 ma will drive DC drives, motors and steam valves. It is a current loop, for long distance transmission, current loop is not prone to noise and hum, EMI RFI. As it is a small power transmission no loss of data, also many [Read More ....]
BD139 and BD140 Complementary transistor This pair is my favorite when driving small solenoids or motors. SOT-32 12 Watts.. BD139 – NPN, 80V and 1.5A, 40 beta min. BD140 – PNP, 80V and 1.5A, 40 beta min. This means any small solenoid, relay or DC motor can be controlled with this. I would use it upto 24V DC and max of 1A for applications of full on and full off. In applications like a regulator or variable motor control, you have to keep in mind the current thru and voltage across the transistor which results in power dissipation. Let us [Read More ....]
Robotics Notebook of Chuck McManis These pages are extremely useful for an entry into the Robotics Wonderland, a little electronics ability is enough for you to start learning robotics. Robotics is the only science that covers everything almost .. Mechanical, Electrical, Electronics, Embedded, Computing, Networking, Automation and Wireless Technologies. Some advanced robots include probably every science and skill known to mankind. So make a start today. Learn Robotics! – ananth (san) PIC Programming using USB, Ant Weight Speed Contro ller, LCD Diagnostic Console, Robotics Projects : Index Tools for Robots The ARBE-ONE Robot The High Power Speed Controller H-Bridge tutorial [Read More ....]
Robotics Institute: Publications This site includes abstracts and bibliographic references for most publications by RI researchers. Additionally, the full text of many of the publications is downloadable in PDF or Postscript format. Technical Reports- published by the RI since 1980. Projects- Projects, Sorted Alphabetically Labs and Groups – Labs & Groups, Sorted Alphabetically The Robotics Institute – Carnegie Mellon University
Aug 252008
School of Analog Design Switching Regulator Fundamentals Objective: Be able to identify the three basic switching regulator configurations and know where each one is used. The course includes inductive switching regulator power stage definition, input, output and duty cycle relationships. Current Feedback Operational Amplifier Objective: This training module discusses the current feedback operational amplifier (CFB op amp). There will be a brief background of the current feedback op amp. DC to DC Converter Basics Objective: This course will teach the basics of linear, inductive, switched capacitor DC to DC converter products from Portable Power Systems perspective. Knowledge Base Design Tools
Good Earthing Prevents Shocks and Prolongs Appliance Life Earthing in the olden days was done like this, i have just mixed what i have heard with my common sense and this is what it may be. Make a deep pit, 4 feet deep, 1/2 feet dia, put long copper rods ( GI pipes or lead pipes were also used). Let the copper rods be driven deeper than the four feet that has been dug. mesh the rods with copper mesh or wire (GI chicken mesh). Fill the pit with all the conductive things which are bio-degradable, non-toxic, non-corrosive and non-soluble. [Read More ....]
