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i was unhappy with my pc board traces, so i covered them all with solder. i rechecked all component placement, values, etc. i tested the transistors, good. i threw together a simple 1500 hz tester for the 741 op amps and discovered that out of a total of 4 that i recently purchased from radio shack,...

i have already sent circuit to forum some time ago. i cannot calibrate this thing. author says, word for word, with all wiring checked, connect a 10-volt dc voltmeter between the common and pin 6 of ic1. with the power turned on, the meter can indicate either positive or negative at this point. conn...

i have just recieved a brand new blue lcd panel meter from hong kong for $8.00. only has 4 connections, 2 for power and 2 for input, great. power is supplied by 9-12 volts ac or dc, great.accuracy is +- .5%, great. there is no data sheet, how do i know what value shunt resistor to use? this is a dc ...

thanks again for your efforts. i am constructing this now, and have found (2) mistakes. c10 is not electrolytic because parts list designates as 2.2uf, 50-volt polystyrene or mylar. secondly, c10 and r25 are in opposite connection on pc component layout diagram. in other words, c10 goes directly to ...

thankyou for all your help. my intentions for the use of the digital meter were to use a separate battery. following authors calibration instructions, i was only going to bring digital meter up to 100ua and not use full range.

transistor q1 and it's associated components form a simple 1-khz phase-shift oscillator that is buffered by q2. the output of q2 is taken from the level control, r9, and applied to the primary of t1. transistor q3 is connected as a constant current source, and its output (collector) is coupled to ic...

your circuit is correct. the popular electronics issue that you have is also correct. i am not as good on the computer as you, but will try to show circuit as requested. thankyou.

circuit is an impedance meter printed in popular electronics october 1972, author is charles d. rakes. was also reprinted in electronics experimenters handbook 1973. out of my hundreds of books and magazines which contain thousands of circuits, this is the only circuit of it's kind.

meter is used to measure voltage. it is wired into a bridge of (4) 1n914 diodes. third bridge connection goes to pin 6 of a 741 op amp. fourth bridge connection goes to pin 2 of that op amp and to a 2.2uf (+) electrolytic capacitor in series with a 10k resistor to pin 6 of a second 741 op amp.as pre...

I AM BUILDING A PROJECT THAT USES A 0-100 UA DC ANALOG METER. I WOULD LIKE TO USE A DATEL/MURATA D20PC-1 LED 0-199.9 UA DIGITAL IN IT'S PLACE. I REALIZE THAT I WILL HAVE TO POWER THE DIGITAL METER. CAN THIS BE DONE? I DO NOT LIKE THE RESOLUTION ON THE ANALOG TYPE AND THE PRICE TAGS.