Transistor Hard Saturation - pg224 - Malvino

Started by veek in sci.electronics.basics3 months ago 2 replies

'A designer who wants a transistor to operate in the saturation region under all conditions often selects a base resistance that produces a...

'A designer who wants a transistor to operate in the saturation region under all conditions often selects a base resistance that produces a current gain of 10. ' http://pix.toile-libre.org/?img=1493526531.png http://pix.toile-libre.org/upload/original/1493526562.png I don't understand what he's doing with the math (it's not complicated math but he's trying to illustrate an idea that I...


one transistor amplifier help

Started by amdx in sci.electronics.basics3 months ago 32 replies

I have the following amp. It originally had a 12V supply voltage, In an effort to get a larger swing on the output, I raised that to 24V. ...

I have the following amp. It originally had a 12V supply voltage, In an effort to get a larger swing on the output, I raised that to 24V. I now get 12.5Vpp on the output, I want to maximize the output signal. A gain of 3 will work for my circuit. What changes can I make to maximize the output swing. The input is at maximum before distortion is seen. > https://www.dropbox.com/s/07j


'K' type thermocouple wire connecting to meter - a question

Started by Charlie+ in sci.electronics.basics3 months ago 5 replies

I have a meter with K type thermocouple. The wire welded blob at the measuring tip is discoloured from the manufacture but apart from that...

I have a meter with K type thermocouple. The wire welded blob at the measuring tip is discoloured from the manufacture but apart from that there is no visible insulation at all to keep the two different alloy wires apart in the fiberglass insulated sleeve (about 1.5 Meters long) that then goes to the yellow plug that fits the meter. I dont understand how the voltage generated in the tip by ...


Thermopile power supply in water heater control

Started by bob prohaska in sci.electronics.basics3 months ago 12 replies

I recently bought a gas water heater and made a point of getting one that didn't require external electrical power to operate. To my...

I recently bought a gas water heater and made a point of getting one that didn't require external electrical power to operate. To my astonishment, it nonetheless came with what behaves like a digital controller, complete with a green LED status light that must require close to 3 volts to turn on. The electronics are operated from a standard Honeywell thermopile generator producing 750 ...


Mystery component marking

Started by Peabody in sci.electronics.basics3 months ago 2 replies

I have two versions of the same USB adapter module. One has what I believe is an SMD jumper marked "000". At the same place in the other...

I have two versions of the same USB adapter module. One has what I believe is an SMD jumper marked "000". At the same place in the other version, the item is marked "T05". Is that also a jumper?


Slip ring questions

Started by Anonymous in sci.electronics.basics3 months ago 16 replies

I'm sure someone here can help. I need to get power to a solenoid operated valve spinning at 5000 RPM. Low power, 24 volts at 5 watts. The power...

I'm sure someone here can help. I need to get power to a solenoid operated valve spinning at 5000 RPM. Low power, 24 volts at 5 watts. The power will be on for about 4 seconds and off for 7 seconds. This on/off cycle will be going on 10 hours a day. I ahve looked at slip rings online but the high speed through hole type are really spendy. Then I got to thinking about the slip rings in altern...


Bnc impedance

Started by jfis...@comcast.net in sci.electronics.basics4 months ago 20 replies

So I am using rg 62 coax which is 92 ohm. My BNC connectors are 75ohm.all my equipment inputs and outputs are 92ohm. Do I need to use 92ohm...

So I am using rg 62 coax which is 92 ohm. My BNC connectors are 75ohm.all my equipment inputs and outputs are 92ohm. Do I need to use 92ohm terminators on all my T's and where,at the source or load? Thanks jf


contact surface material

Started by malua mada! in sci.electronics.basics4 months ago 7 replies

I made an exposed lid switch consisting of two mating pairs of flat brass stock about 1 x 1/2 inches. When I close the lid they make contact and...

I made an exposed lid switch consisting of two mating pairs of flat brass stock about 1 x 1/2 inches. When I close the lid they make contact and 12VDC flows into 2.5 ohms worth of nichrome heating wire. The idea being NOT to have live voltage exposed when the lid is open. Also, wire fatigue was causing problems. However, the contacts get dirty. They develop carbon scabs and get hot.


Ground is no longer at ground potential

Started by Anonymous in sci.electronics.basics4 months ago 36 replies

Scientists have determined that ground is no longer at ground potential. It dont matter if you're referring to the ground for your...

Scientists have determined that ground is no longer at ground potential. It dont matter if you're referring to the ground for your home's electrical system, or the chassis ground in an electronic device. Due to changes in the earth's structure, caused by both natural causes, such as shifting of the earth's plates, and man made deviations of the earth caused by excessive pumping of oil, over...


Transistor circuits, book, devices, etc

Started by Peter Percival in sci.electronics.basics4 months ago 51 replies

I though I'd like to learn a bit about electronics and to that end I'd like to buy a book of transistor circuits, a breadboard, and various...

I though I'd like to learn a bit about electronics and to that end I'd like to buy a book of transistor circuits, a breadboard, and various components to experiment. Can anyone recommend a book that uses transistors that I can buy in the UK? Also, who is a good supplier of components generally? -- Do, as a concession to my poor wits, Lord Darlington, just explain to me what you reall...


Ask a Question to the Electronics-Related community

To significantly increase your chances of receiving answers, please make sure to:

  1. Use a meaningful title
  2. Express your question clearly and well
  3. Do not use this forum to promote your product, service or business
  4. Write in clear, grammatical, correctly-spelled language
  5. Do not post content that violates a copyright