Connection from power transistors to printed-circuit board

Started by Anonymous in sci.electronics.basics8 years ago 11 replies

hi group, i'm planning to build my own power amps and i've narrowed down my choices t= o the LM3886 and one of the LMEs (49810 or 49811 or...

hi group, i'm planning to build my own power amps and i've narrowed down my choices t= o the LM3886 and one of the LMEs (49810 or 49811 or 49830), but i'm very mu= ch tempted with the LMEs (main two reasons: higher audio quality and config= urable power -- that is, i'm not stuck with 70W; i can choose the right tra= nsistors and the right supply voltages and i can build a 50W amp, or 100W, ...


?s on identifying a 555 timer chip

Started by Dave in sci.electronics.basics8 years ago 11 replies

Here's one... If I had a circuit that made use of a 555 timer chip, but it was not marked in any way that I could identify as the markings or a...

Here's one... If I had a circuit that made use of a 555 timer chip, but it was not marked in any way that I could identify as the markings or a 555, how could I confirm that it was indeed a 555 timer chip? Still working on wireless remote for automatic door opener that doesn't. I believe I have confirmed proper function in the three transistors, but it looks like the oscillator isn't ...


How the circuit works

Started by Anonymous in sci.electronics.basics8 years ago 6 replies

Whenever I try to understand explanations of how a circuit works these seem very complicated and confusing. There will be some general lines to...

Whenever I try to understand explanations of how a circuit works these seem very complicated and confusing. There will be some general lines to understand how a circuit works from some transistors to a dozen or more of them. Thanks in advance.


Current limiter that doesn't

Started by Douglas Beeson in sci.electronics.basics7 years ago 2 replies

Hi all, I'm stuck. I am trying to limit the current flowing through a relay by using two transistors and a current-sensing resistor. Schematic...

Hi all, I'm stuck. I am trying to limit the current flowing through a relay by using two transistors and a current-sensing resistor. Schematic below. The Spice model works beautifully, but the real world circuit does not turn off. Ever. It just fires once the first time the timing pulse arrives, then stays on. My goal is 70 mA through the 70 ohm load above the Q1 collector. The measured curr...


Where to buy these electronic components for my project?

Started by Skelton John in sci.electronics.basics7 years ago 18 replies

Hi, I am new here. I am a designer at an electronic company. Now I want to design some gadget for hobby. Operation Dancing Light, circuit...

Hi, I am new here. I am a designer at an electronic company. Now I want to design some gadget for hobby. Operation Dancing Light, circuit diagram: http://4.bp.blogspot.com/-xk6tMYM9zBk/VOq7IiC_T-I/AAAAAAAAARI/4mazrjp0RmQ/s1600/Christmas1.png Parts List All the base presets are = 10K, All the collector resistors are 470 Ohms, All the diodes are = 1N4148, All NPN transistors are = BC547, The...


Oscillators without transistors

Started by Anonymous in sci.electronics.basics3 years ago 24 replies

Hello, What are some examples of oscillators which don't require transistors or vacuum tubes? So far I found relay oscillators and the...

Hello, What are some examples of oscillators which don't require transistors or vacuum tubes? So far I found relay oscillators and the Pearson-Anson oscillator. Does the Pearson-Anson oscillator require a high-voltage neon lamp, or would it work on LEDs as well? https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect Relay oscillators look neat too but I don't imagine they would la...