Need Ideas for Beginner Analog weekend project - Page 1
Forum section: electronics / beginners

author: Jebnor
author_rank: Regular Contributor
timestamp: September 20, 2013, 09:46:29 pm
content: I need a project for the weekend. Something simple(ish) made with common parts. Nothing beyond lm741 or 324s. If they could be all discreet that would be better.Fire away.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: September 20, 2013, 09:51:12 pm
content: http://www.eevblog.com/2010/08/01/eevblog-102-diy-constant-current-dummy-load-for-power-supply-and-battery-testing/

author: firehopper
author_rank: Frequent Contributor
timestamp: September 20, 2013, 09:51:56 pm
content: why not a 2 transistor oscilator. blink 2 leds.

author: Jebnor
author_rank: Regular Contributor
timestamp: September 20, 2013, 09:59:18 pm
content: Quote from: Galaxyrise on September 20, 2013, 09:51:12 pmDone.Quote from: firehopper on September 20, 2013, 09:51:56 pmAnd Done using Andy Davis' Land cutting method

author: AG6QR
author_rank: Frequent Contributor
timestamp: September 20, 2013, 10:02:54 pm
content: It's hard to give meaningful suggestions without knowing your level of equipment or experience, as well as the parts you have on hand, but here's mine anyway.Make a Wein bridge oscillator. Use a flashlight bulb in the feedback loop, the way Hewlett did in the original HP200A. See how pure of a sine wave generator you can make, and you might consider making its frequency adjustable over a very wide range.After that's done, if you want more, modulate the gain and make an AM radio transmitter out of it.

author: Jebnor
author_rank: Regular Contributor
timestamp: September 20, 2013, 10:20:51 pm
content: Quote from: AG6QR on September 20, 2013, 10:02:54 pmGood point. I come from a digital background and would like to learn more analog. I have an oscilloscope, multimeters and a couple power supplies and batteries.Here is what I have.Transistors:NPN/PNP 2n3904/2n2222/MJE3955 and complements.J177, 2n7000, VP0300L, VN0300LResistors & caps:E3 Resistors 10-1ME3 Caps. 10p-1000uVarious Potentiometers.Diodes:1n4148various Zener 3v6-16Rectifier 1n4007 & such1n34a26g & 18g magnet wire -- No ferritesPCBs and such.

author: JackOfVA
author_rank: Unknown
timestamp: September 20, 2013, 11:45:44 pm
content: Perhaps a two stage audio amplifier with discrete transistors. An NPN input/driver stage and a complementary symmetry output stage with PNP & NPN to drive a speaker or resistor dummy load.This is a good starting point as you can calculate with paper and pencil the required component values and then you can build it and see how close to your calculations the amplifier is when built. Can all be done on a solderless plug board and you have the equipment to measure DC Q-point and AC frequency response. You can also vary the drive and observe clipping/saturation on the oscilloscope. Change component values such as emitter bypass capacitor or coupling capacitors and see how that alters performance.It would be nice to also measure distortion, may be a bit tricky to do accurately with just an oscilloscope other than gross waveform distortion. You can do some simple things like input to channel 1 output to channel 2 and select XY mode and observe the phase shift and clipping. Or you could try Chan 1 - Chan 2 mode which would, in theory, subtract the two signals leaving only the distortion products, but that's one that works better in theory than in practice.

author: Jebnor
author_rank: Regular Contributor
timestamp: September 21, 2013, 05:37:24 am
content: Quote from: AG6QR on September 20, 2013, 10:02:54 pmAt first I didn't know if I wanted to do this, then I looked into it a little. It's now 4 hours later with a couple journal articles, HP stuff and Thoughts on where to get a nice lightbulb.I think we have a winner. Next weekend, The 2 stage audio amp.

author: zapta
author_rank: Super Contributor
timestamp: September 23, 2013, 05:56:50 am
content: Get also a few op amps. They are very useful.For next week try to build an white noise generator. The following week, a negative resistor.

author: Paul Price
author_rank: Super Contributor
timestamp: September 23, 2013, 10:11:08 am
content: You need more active devices to play with, all your stuff is so passive. The real excitement in electronics is working with devices and chips that can do something besides prove the laws of entropy.Make a small, handheld, useful thing, like a kitchen timer, just requires something to set a time interval and a way to show someone it has run out of time. Not too complicated if you keep it simple. Makes a nice gift to a loved one or someone you wanna make time with. Keeps you from burning the eggs for breakfast.Nothing like working with realtime machines.