What does the project present?
An audio frequency generator is an electronic assembly that must not be missing from the workshop or laboratory of any amateur electronics technician.
Such a generator can be used in the most diverse electronic applications: debugging, generation of onomatopoeias, checking of audio frequency amplifiers, electronic sirens, etc.
How does the circuit work?
This vintage DIY electronic kit is an audio frequency generator made with the CBD 400E integrated circuit (SN7400). With the help of three YES-NO gates and several resistors and capacitors, a frequency of approximately 1 KHz is generated.
The signal generated by the assembly is reproduced with the help of a headset of impedance of approximately 50 Ohm. It is recommended to power the entire assembly from a 4.5V battery or from a stabilized 5 volt source.
Technical characteristics of the assembly
- Vcc power supply = 5V (battery or DC voltage source)
- Telephone headset: impedance Z = 50 Ohm
List of required components (with recent equivalents):
- CI - integrated circuit B400E or SN7400
- C1, C2 - capacitors - 0.22 uF (min. 100V)
- C3 - capacitor - 47 uF (min. 12V)
- R1, R2 - 2.2 KOhm resistors (min. 0.5W)
- 50 Ohm headset (small Chinese speaker recovered from a portable radio or a walkman headset)
- Printed wiring or breadboard test board
- Tin or connecting threads
Download the original IPRS leaflet Baneasa 8108
For a better understanding of the operation of the circuit we will need electronic scheme presented below:
In order to carry out this project in our own laboratory, we will also need printed wiring PCB layout From lower:
Many of you are probably wondering how this DIY electronic kit was packaged or distributed. Below I have attached a picture with packaged product (new). Thanks sir. Marius Balauta!
Also, in order to better understand the operation of the presented assembly, I also attached catalog data for CI CBD 400E:
I have attached below an image with assembled assembly. The speaker is not part of the kit.
It was nice to be able to connect to the antenna input of a black and white TV. The "surprise" was that at one point some black and white bars appeared in the manual search. That kilohertz had thousands of harmonics and that's what happens. I was instructed not to connect in vain through the TV, not to remove the cover…. Crazy times.
I made it too. And playing with a diode between different points, my TV went crazy, the image waved and the sound was uncontrollable! I was having fun with friends with the toy in my pocket!
Hello, I have a question too. I have a lot of Baneasa IPRS wiring. How do I get schemas and parts lists?
You can download or view the original IPRS Baneasa leaflets from the articles. You have a "download" button.
We dreamed of an oscilloscope. In 1968 it seemed fantastic to me.
I built this one and modified some capacitors and resistors for other frequencies. I even came across him the other day.
CDB400 = SN7400 but SN74LS00 and SN74ALS00 or SN74F00 can also be used.