Ceiling Fan Repair Tutorial Part 2
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Nmos Power Amplifier Series Part 1
Nmos200 - TO220 A compact power amplifier module capable of up to 200 watts into a 4 ohm load depending on power supply and the output mosfets used. The module is limited to rails of +/- 50v max. The amplifier can be built using either TO220 or TO247 style Mosfets. Schematic Diagram Nmos200-TO220 Layout Nmos200-TO220 Nmos200 - TO247 Nmos200 - TO247 Stereo Schematic Diagram Nmos200-TO247 Layout Nmos200-TO247
Hofner Colorama II restoration project part 18 rescuing a ruined finish
Well, it happens. You have a lovely finish on your guitar and then you drop it, chip it, scratch it, or whatever. In my case I got a bit overly energetic while polishing it and this happened: It probably didn’t help that the lacquer hadn’t completely cured so was still a little bit soft. I’m sure there’s a term for this, but I can’t for the life of me remember what it is. The long and sort of it is that I friction burned it, causing the lacquer to melt and shift. First things first, I decide to scrape off the raised lacquer with one of my favourite new tools, the razor blade: This leaves us with the following: Next, I carefully sand away any remaining effects left by the original melting using 400 grit paper wrapped around a wine bottle cork: This leaves us with this (you know that expression about things getting worse before they get better?) Next, we go over it with 600 grit paper, again wrapped around a cork (800 grit would be better if you can get your hands on some): Leaving us wi...
Semi Conductor Tester SemTest Part 4
Testing was done in part 3, this last part is consist of following: Final assembly The front panel assembly can now be lowered down onto the case. Make sure that the three ribbon cables are folded neatly into the space above the lower PCB and not caught between the edges of the case or lid. Fasten the case together with four M4 screws into the corner holes, then fit the knobs to the rotary switch and the pot and the assembly is complete. Testing the HV crowbar It’s now necessary to check that the HV crowbar circuit is working correctly. To do this, power up the unit, wait a few seconds and then press the Menu Select button. You will get a display like this: Device to Test:▲ 1:Diode/Zener▼ Press Enter and then the Up button. The display will then show: Test parameter:▲ Irev(OPV)▼ Press Enter again. Set the Device Operating Voltage to 25V, using the right-hand knob. Then press the Test On/Off button to start the test. Now careful...
PICAXE Programming Basics Part 2
Recommended Level Beginner Recommended Prerequisites Introducing the PICAXE System PICAXE to PC Connections PICAXE Programming Basics - Part 1 Introduction Part 1 of PICAXE Programming Basics included full information for assembling a PICAXE programming test circuit. That circuit will be used again in this article, so be sure that you have the assembly connected to your computer via your programming cable. Although not absolutely necessary, a review of programming using AXEpad will facilitate learning to program using PICAXE Editor 6. PICAXE Editor 6 PICAXE Editor 6 (PE6) is the recommended Integrated Development Environment (IDE) for users of personal computers using Windows XP, Vista, 7, 8, and 8.1 operating systems. PE6 is the successor to Programming Editor 5, but is all new; none of the code from PE5 was reused. In addition, complete flowcharting capabilities are included in PE6, making Logicator unnecessary. However, Revolution Education (Rev-Ed)...
12 24v High Current Motor Speed Controller Part 2
In first part we discussed about the detail of circuit, back EMF and Mosfet protection; in the second part we will cover these: Other protection measures As already mentioned, diode D1 provides reverse polarity protection for microcontroller IC1 and the switchmode supply (IC2). Zener diode ZD1 is self-protecting in the case of reverse supply connection. However, if the supply is reversed, there will be a heavy conduction path via fast recovery diode D3 and the internal substrate diodes in the four power MOSFETs. If you are lucky, the 50A fuse will blow before the MOSFETs are damaged, but there is no guarantee of this. SO dOn’T rEVErSE THE bATTErY cOnnEcTIOnS! In a similar vein, if the outputs are shorted while power is applied, high current will flow through the MOSFETs. Again, if you are lucky, the 50A fuse will blow before the MOSFETs go up in smoke. In reality, the 50A fuse is there to stop a fire! SO dOn’T SHOrT THE OUTPUTS TO THE MOTOr. If the motor is under heavy load ...