I have a symbol on my schematic but I cannot figure out what is this? I looked through Internet and didn't find anything( enter image description here

Is this a microphone? If so give me some helpful links to learn something about it. I have to draw this element and make a pattern for it. So links for pattern would be also great. The whole scheme looks like this:

enter image description here

  • 8
    \$\begingroup\$ It could be a motor, a meter or a microphone, or anything else you can come up with starting with M (except MOSFET). It might even be a marmoset, though what that would be doing in a circuit is anyone's guess. Some context would be kind of useful - see where it is in the circuit and what it does. \$\endgroup\$ – Majenko Oct 31 '16 at 21:55
  • \$\begingroup\$ Please share a picture of the whole schematic diagram. \$\endgroup\$ – zack1544 Oct 31 '16 at 21:56
  • 1
    \$\begingroup\$ Most likely it's an electric motor but Majenko is correct it could be something else. Here is a link to some common schematic symbols: rapidtables.com/electric/electrical_symbols.htm \$\endgroup\$ – DigitalNinja Oct 31 '16 at 22:03
  • 6
    \$\begingroup\$ To be more specific, it's a DC motor, that's why the straight line is below the M. \$\endgroup\$ – Janka Oct 31 '16 at 22:07

Now you've added the full schematic, that's almost certainly a motor and not a microphone.

The four MOSFETs, VT3, VT4, VT5, and VT6 form an "H-bridge" circuit which is a very common way of driving a motor with bidirectional control.

  • \$\begingroup\$ I once heard a voice coil (VCM) sound like R2D2 with a bridge circuit exactly like this. It was the 1st Maxtor 5.25 " rotary actuator doing a servo spectral calibration sweep. \$\endgroup\$ – Tony Stewart EE75 Oct 31 '16 at 22:47
  • \$\begingroup\$ @SunnyskyguyEE75 I almost fell out of chair reading this. Reminds me of one of the SCSI bricks used for seismic tests. Normally quite, when the data started streaming in you could track which stack was in use because the stack in use (which had 8 drives) would start screaming... \$\endgroup\$ – GB - AE7OO Aug 27 '19 at 6:55
  • \$\begingroup\$ @GB-AE7OO yes the sounds of disk drives are very interesting and have many reasons. From all my career in design, mfg. and test in every field of aerospace, nuclear, telecom, RF, although conceptually simple in isolating each detail of the electro-magnetic-mechanical-acoustic design, nothing packs more design technology in a little box than any HDD. Anyone who wants to learn decades of design technology just has learn how to reverse engineer an early -80’s HDD. Nothing else compares. Maxtor NPL-Hitachi, Toshiba, Seagate, Fujitsu, amazing \$\endgroup\$ – Tony Stewart EE75 Aug 27 '19 at 8:11
  • \$\begingroup\$ @SunnyskyguyEE75 I remember my first 5MB MFM drive(FH). Fun playing gyro with it...:) Right after I got out of the Navy in '90 I worked field service in the POS field, and one of the systems I worked on was the Sweda 80S system which was a re-badged Data General NOVA system, talk about disk drives(these things had disk packs about 18" wide), still have about 5 of the platters that house various awards... \$\endgroup\$ – GB - AE7OO Aug 28 '19 at 1:22
  • \$\begingroup\$ @GB-AE7OO yah me too. My 3rd employer after 9 yrs was Burroughs in Winnipeg , the peripheral plant hired as a Test Engineer for 5.25” 5MB cartridge over 5MB fixed by DMA in Santa Barbara. In ‘83 so I got to learn all bout them rotating memory products while the factory still made 14” products the size of a stove with a 1Hp linear motor. In both fixed and pack drives. Hang on to those beauties, the awards = priceless. I really enjoyed that era and Silicon Valley, and later offered QA Mgr job a few years at Seagate, but ex-wife no move. Those linear motors were later used for ventilators. \$\endgroup\$ – Tony Stewart EE75 Aug 28 '19 at 2:17

Well, this picture is a circuit drawn according to Russian standards, so that symbol meaninig is exactly "DC motor".


Looks like a motor controller circuit.

Uynp1 and Uynp2 are two H-Bridge controls for direction and stop and the rest of the circuit is a interesting dead time or perhaps a dynamic breaking mode control.

The line under the M is likely an inhouse differentiator. With an AC motor it might have a ~ (tilde) character under the M instead of the - (dash) for DC motor.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.