> Looking for recommendations for a reasonably-priced (but decent, reliable) > DMM (I just blew up my ancient RS analog meter). Seems to be a plethora of > them out there. Jameco has a handy selection guide in their catalog, but I > wondered which features (e.g auto-range, capacitance, freq. etc) folks > consider must-have, nice-to-have, worthless. You'll get lots of thoughts on this. Here are a few very quick ones, some not quite the normal things you may think of, - I prefer seperate on/off button as it lets you leave meter in circuit on range desired if needs be. Some prefer the "turn the main switch to the off position" style but I can't imagine why. Auto off saves batteries BUT is very annoying if it can't be disabled and keeps happening while you are moniytoring something. As I may have quite a few meters running at once and have a habit of leaving them on occasionally I use cheapest possible batteries and replace as needed. This may sound trivial but is, IMHO, a very important fearure. If AT ALL POSSIBLE the meter should have a continuity beeper that sounds IMMEDIATELY he probes are shorted - NOT after the meter has auto counted down or thought a while. Very very useful for circuit continuity testing. Slow beep response is very very very annoying. eg you have a 40 pin header and want to know which pin the green wire goes to. With fast ohms beep you just run the probe along the connector pins quite rapidly and get a beep as you pass the correct one and then go back to check which one of several it was. With slow ohms beep its connect, WAIT, connect next pin, WAIT, connect .... - and as you don't know just how long to wait it can be very slow indeed. Be aware that some meters become inaccurate, sometimes VERY inaccurate when battery is almost flat and that some do not have a low battery indicator. I would avoid such meters if at all possible. Unless you religiously check calibration before each session of use this can be a very bad trap. This is not hard to test for but is a little annoying to do. Take an almost flat 9 volt battery with you (or even two at say 6 volts and 7 volts) and see how the meter behaves. Also take a known good voltage source (such as a new 9v battery you have checked already) and see what it says its voltage is. You want a minimum of 3.5 digits (0-1.999). Some meters have 4.5(0 - 1.9999) digits or 4 digits (0 - 9.999) which is nice. Actual accuracy may not be much higher but the ability to read over awider range can be very useful. eg if you are deading a 3 to 4 volt signal you will have to use the 20 volt range on a 3.5 digit meter and only get 3 digits and the 4 v signal will only be 20% of the max range so accuracy will suffer. On a 4 digit meter you use the 10 volt range and get 4 digits as well. Actual accuracy specs should be checked - number of digits and accuracy may be very unrelated :-) True RMS capability is nice but not essential and often adds greatly to the price. An "analog" bar graph as well as the main digital display is useful for rapidly varying readings. (Can't beat true analog for some thingsif you don't have a scope). Peak hold is useful but not essential. At least a 10 amps DC range. AC amps is nice but less useful. Ensure current ranges go LOW enough - it's nice to have a single uA as the lowest digit eg 0 - 1.999 mA even if the accuracy is suspect. (eg How much current does my PIC draw in full shut down? Why is it 40 uA and not 4uA as I would have expected?etc). Transistor beta is commonly available and quite useful. Frequency measurement is usually done via analog conversion which is a poor way to do it but can be useful. Auto ranging can be useful but is often more trouble than it is worth. Capacitance is useful. Inductance is useful but rare. Really high ohms ranges (400 Megohm) is useful in some cases for eg insulation testing BUT the voltages used are too low for serious megger use and the response times are deathly slow. Many people would say you will never be sorry buying a Fluke. They are very nice (often) but seem over-priced to me despite what you get UNLESS you want professional class accuracy and quality. I've never owned one. More could be said but that will do for now (amazing how much you can look for in a cheap meter :-) ) regards Russell McMahon ----- Original Message ----- From: Gary Russell To: Sent: Sunday, March 24, 2002 8:51 AM Subject: [EE]:DMM Recommendations?? > Looking for recommendations for a reasonably-priced (but decent, reliable) > DMM (I just blew up my ancient RS analog meter). Seems to be a plethora of > them out there. Jameco has a handy selection guide in their catalog, but I > wondered which features (e.g auto-range, capacitance, freq. etc) folks > consider must-have, nice-to-have, worthless. > > TIA > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads