Circuit Ideas - Remember these?

[reubensm]

Hi all, duing my childhood I used to eagerly await dad bringing home the latest copy of Electronics For You magazine (he also brought home to special editions once in a while). Without doubt, the section of the magazine which I used to look forward to was "Circuit Ideas". I still recall building my first circuit idea, a simple medium wave transmitter by Sandeep Bhagchi. Recently came across this page which had a lot of those simple circuit designs. Brought back the memories of old. Thought I'll share this with you all. There are some pretty interesting circuits on this page, including some phonostages in the audio section.

http://www.seekic.com/circuit_diagram/Audio_Circuit/

 

[suraj]

I do!
I had a kit-It came with a 555 ic,and a assortment of components,so that i could make all sorts of things with it- a metronome,buzzers,ldr based triggers,relay activators,fire alarms etc.
It was a sort of solderless breadboard-it had springs and all wiring were done by placing leads into the spring and snapping it shut.

That,and a electricity and magnetism kit-with fans,bulbs,magnets,wire inductors,capacitors and all!I spent months fiddling with those!

Dont know if you get them anymore.

 

[reubensm]

I do!
I had a kit-It came with a 555 ic,and a assortment of components,so that i could make all sorts of things with it- a metronome,buzzers,ldr based triggers,relay activators,fire alarms etc.
It was a sort of solderless breadboard-it had springs and all wiring were done by placing leads into the spring and snapping it shut.

That,and a electricity and magnetism kit-with fans,bulbs,magnets,wire inductors,capacitors and all!I spent months fiddling with those!

Dont know if you get them anymore.

I used to have the one with the 555 timer IC, maybe not exactly the one which you had but it was a educational kit from Hong Kong. I remember making a automatic traffic light with it, for a school exhibition. It was great fun in those days.

I used to build experimental projects, without a bread board or PCB. I used to make use of the plastic lids of old pencil boxes and lunch boxes. These were the very early days. I remember building my first low power amplifier on a piece of salvaged PCB (had the tags below, removed). I still have that unit with me Other things built were, MW Transmitter, a lot of preamplifiers, cassette player, a lot of power amps for friends, a 14 inch black and white television, pocket radios and 2 band radios, to name a few. I still recall how my brother and I graduated from mono to stereo with a TBA810 based stereo amplifier. I was in standard 9 at the time and that was a big hit amoung our class mates. Imagine, back in 1987, not too many school students back at school had a stereo cassette player, stereo amplifier and 2-way floor standing speakers (that too, all DIY)

I still remember, the very first cassette we played back in stereo after the DIY job was the OST of Top Gun

 

[anuragn]

How can I forget. I never bought EFY, but used to read it in our school library. And whenever I found an interesting circuit, I would draw it in my notebook. No Xerox in those days! It was late 80's, and I was in std 9 when I started this hobby.
And of course, a board of TBA 810 connected to my walkman was the first casette player of our house, which I later upgraded to stereo using a second TBA 810 board.m I

 

[wlg]

I built my first AM transistor radio while in school in 1968 using Tr OC71 & OC72, at that time IC's were not in the market, spent a lot of time at Lamington road buying circuit books and experimenting, built my first amp 1972 using valves EL84, ECC83 ECH81 (if I remember correctly) and got a carpenter to build my spkr box, used pioneer 4" tweeters & 8" dual cone philips spkrs, used my BSR TT, now all I have left are my LP's.

 

[linuxguru]

I built my first AM transistor radio while in school in 1968 using Tr OC71 & OC72...

Ah, an old-timer. I built my first AM transistor radio (from a published DIY Ladybird book) in 1974 with OC45 (RF amp), OC71 (gain) and OC72 (AF amp) - no IF stages, etc. Tuning selectivity was not great (just had a coil wound on a ferrite rod and a ~500 pF variable tuning cap in parallel as the RF tank), but it worked. I also built a 2 transistor radio later - just LC tank, OA79 detector and 2-stage AF amp.

Both on wood breadboards, one with screws to hold brass tags to solder on, and another with just bare wires glued onto the board with quick-fix, and components soldered directly to the bare wires.

This was long before EFY, Elektor, etc. However, there was Science Today, which had a DIY electronics column written by one Anil V. Borkar. He published some moderately complicated DIY designs for that time, including a reel-to-reel tape recorder in 2 or 3 parts, a Hi-Fi Audio Amp (using a quasi-symmetrical design with AD149 outputs) in 3 parts, etc. I built many of the simpler audio oscillator and amplifier circuits published in Science Today in the mid- to late-70s (before the IC opamp era in India). To my recollection, the first 741s started showing up in the late '70s locally, and were moderately expensive - the BEL clone was called CA741 or something, and had gold-plated leads.

The early 80s witnessed the BEL Versawatt (TO220) power transistors, in both NPN and PNP - a minor miracle, because there weren't many locally-available inexpensive complementary power transistors before that. This allowed an entire compact Class-B power amplifier to be built with just a 741, 2N6107 and 2N5294 or something. Around the same time, the first moderately powerful chipamps - LM386, and then TBA810/CA810 also showed up, and greatly lowered the cost of commodity mid-fi amps.

 

[suraj]

I used to have the one with the 555 timer IC, maybe not exactly the one which you had but it was a educational kit from Hong Kong. I remember making a automatic traffic light with it, for a school exhibition. It was great fun in those days.

I used to build experimental projects, without a bread board or PCB. I used to make use of the plastic lids of old pencil boxes and lunch boxes. These were the very early days. I remember building my first low power amplifier on a piece of salvaged PCB (had the tags below, removed). I still have that unit with me Other things built were, MW Transmitter, a lot of preamplifiers, cassette player, a lot of power amps for friends, a 14 inch black and white television, pocket radios and 2 band radios, to name a few.

Even i had a hong kong make kit!It gave me quite some clout among friends as,back then,it was really something to have video games from Dubai and foreign made toys.

I still have the old Science-today copies and the occasional indrajal comics which came as part of offers(I was in Ernakulam back then).would run to the bus stop and wait for the paper chaps to drop off the consignment of magazines.

I never got to use a soldering iron till a few years back-though i still remember trying to solder back wires and loose battery connections using a needle heated over a wood fire.
As for radios-i never got them to work really,though i was an expert in fixing the old pulley-and-thread radio tuning mechanisms,disconnecting the dial backlight to annoy elders and all.Got an uncle to do all the soldering for me.

 

[grubyhalo]

Yup, this was a favorite of my dads and I used to browse through it looking for new products. My dad may still be subscribing to this, I'm thinking...

 

[baijuxavior]

This brings back old memories. Back in the 90's my brother used to assemble amplifiers and repair radios. In those days my ambition was to be an electronics guy like him - to assemble a tape deck and play music at high volume. I used to read EFY and a similarly named malayalam electronics magazine (EFE). After passing Pre-Degree, I wanted to join BSc Electronics but ended with Physics, which also had some electronics papers. I used to visit the college library just to read back issues of EFY. I read the circuit ideas eagerly. Articles I liked most were about digital clock, fm transmitter and amplifiers. I even tried a few amplifiers, automatic bulb switch based on ldrs etc. However now a days I rarely do any electronics stuff. Infact I even forgot how to read resistor color codes. The soldering iron is now mainly used for making holes in plastic.

 

[reubensm]

I remember, whenever we used to go to the British Library and would fine a nice practical circuits book, most of the key project pages were torn away

EFY and Elektor were standard staple at home. These days, my career and family take a lot of my day, so can't really pursue my hobby. Plan is to keep the hobby on hold and focus on my career fullyl, so that I can retire about 10 years earlier and then divert all my attention to my hobby. I always had this plan to build a tube amp, horn speaker cabinets, learn carpentry, etc. I would like to assume that 50 is a good age point to start.

Restoration projects completed in the last 1 year:

1) Grundig CF5500 Cassette Deck
2) Grundig V5000 Integrated amplifier

Upcoming Projects:

1) Vintage Garrard RC210 Record changer restoration (parts awaited from the UK)
2) Vintage Akai GX630D r2r deck restoration (this is a pristine piece of equipment and in brand new condition but needs to be properly serviced and calibrated as it was in storage for 30+ years)

 

[HiFiManish]

Me too had been on same boat!
My father is an electronics hobbyist and had been a subscriber of EFY and elector electronics since the late seventies / early eighties.
Many of the copies are still intact with him. On one of my b'day I had got the chip chap kit ( the 555 IC based) which was a major distraction for my acedemics of that year.

those were the days!

 

[Audiodoc]

Me too. The project of the month was always out of budget but these circuit ideas were great. Although some were buggy.


i can remember a few circuits used to come in physics for you magazine too however I drooled over the elektor ones especially high end audio amplifier. Made a few though in 1996.

 

[sbg]

Electronic Piano was my first based on 555 timer - organ . Some 12 keys based.
Completely housed in DIY box, with Keys made out of teak-wood, the contact points were lead and wire on "Drawing pins". the key press action was controlled by a sheet of packing foam.

at later stages mosquito repeller, FM transmitter ....

I usually use to get the special and annual editions.

 

[reubensm]

On one of my b'day I had got the chip chap kit ( the 555 IC based) which was a major distraction for my acedemics of that year.

those were the days!

Its funny, how circumstances are similar for all of us, this hobby was always a major disctraction for my academics as well.

 

[Audiodoc]

Yes I also made the circuits noted by Sbg. Had a commondo raid on my house after making the fm transmitter as I used to live near an army cantonment in Kashmir.

 

[suraj]

^Whoa!0_o
so,what was their reaction when they found that it was you?
What happened next?