>I have a transformer with 4 leads on the AC side and 6 on the output side. I'm a bit confused...I'm used to 2 on the input side and 3 on the output. Any idea how to even test the transformer? I tried measuring the ohms....they are all very close.... Usually this is done with a Variac, a variable AC transformer. Connect to a pair of leads and slooowly turtn it up from zero to mains voltage while monitoring input current and output voltage. Try connecting this to the highest impedance leads first, most likely to be the high voltage input. You simply have multiiple taps that produce several AC voltages. Often the input leads will be a different kind of wire. Other than that you can use the ol' circuit breaker method (ka POW!) If you know the rated input wattage, you can also do a shorted test. You short the output leads, and turn up the input voltage until it draws rated wattage, then measure the output current to get an estimate of the rated output current. This is, of course, a dangerous test if you don't know the rated wattage...... >Another transformer I have is 110 to 16 volt...I hooked it up backward to see if I could get a few hundred volts AC...nope...it popped my circuit breaker....why did it not act as a step up? Do I need to limit the current I feed it? Well, several things could have happened. First, your low voltage winding is liable to be low resistance resulting in large currents, blowing a breaker. Second, if that doesn't happen, you likely exceeded the voltage rating of the windings on your high voltage windings, causing them to arc, and short, once again blowing a breaker. You really need to be using a variac with this sort of thing. You can fake it with a set of known low voltage AC transformers - test at 6V then 12V then 48VAC then twice 48VAC etc. Or, you can simply excercise your circuit breakers a lot >And hearing Ultrasonic. I want to audibly hear the output of a ultrasonic transmitter....can I build an amp that shifts the frequence down to a level I can hear via a speaker? Any ideas? A crude way might be to set up a comparator to convert the ultreasonics to a square wave, then measure the pulse widths with a PIC, and simultaneously output every third pulse with the PW multiplied by three (or some number) You could record the stuff directly into a memory using A/D then play it back later at a lower baud rate... You could record it on magnetic tape and play it back a t a lower speed like us old timers did (got any reel-to-reel tape players laying around?) there might be a way to hack one of those keen sound chips to record at a high data rate and play back at a low data rate... >Thanks for hearing me out...I know these are newbie questions.... Pun taken. -- Lawrence Lile Tim Hart Sent by: pic microcontroller discussion list 11/10/2003 04:44 PM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: [OT]: Simple questions... HI all...I have a few quick simple questions for the group... I have a transformer with 4 leads on the AC side and 6 on the output side. I'm a bit confused...I'm used to 2 on the input side and 3 on the output. Any idea how to even test the transformer? I tried measuring the ohms....they are all very close.... Another transformer I have is 110 to 16 volt...I hooked it up backward to see if I could get a few hundred volts AC...nope...it popped my circuit breaker....why did it not act as a step up? Do I need to limit the current I feed it? And hearing Ultrasonic. I want to audibly hear the output of a ultrasonic transmitter....can I build an amp that shifts the frequence down to a level I can hear via a speaker? Any ideas? Thanks for hearing me out...I know these are newbie questions.... Thanks, Tim -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.