From FB group Building Transistor Radios, 2018-09-02 I already see one mistake. On p.27, Audio Mixer. The R6 is only 1k. The voltage divider R5 and R6 will give a voltage less than 0.6 at Q1’s base, which means Q1 will not be forward biased enough and the circuit won’t work or else sound distorted.
(Read More…)
From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is
(Read More…)
From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is
(Read More…)
From FB group Ferrite Loopstick Antenna Experimenters Some experimenters in another group looked at schematics and saw that some radios with a RF amplifier between the loopstick and the converter used a third section on the variable capacitor to tune the RF amplifier. This is good, but it makes the variable capacitor more expensive and
(Read More…)
From FB post One important thing that people forget to do is consider what might happen with a circuit that has anything that draws power from the protoboard. If you’re working with a few low power devices such as small LEDs and switches, then there is usually not a problem. But if you have a
(Read More…)
I was reading this blog, and I’m referring to this schematic. The author calls this regenerative receiver a “minimalist” design, but I refuse to consider a circuit with 7 transistors minimalist. If one thinks of the design as constrained to using a supply voltage of only 1.2 volts, a single AA or AAA rechargeable NiMH
(Read More…)
I pulled a pill bottle out of my junk box, it had a single layer of solid enameled wire wound on it, and it measured 85 microhenrys. So I added the transistor, resistors and the capacitors to get it to oscillate at the low end of the AM BCB, around 540 kHz. The schem is
(Read More…)
I’m building a tuned circuit tester, which is a Franklin Oscillator without the parallel tuned circuit. I based it on the schematic I found at this URL. The first amp is a JFET in common drain or source follower configuration, which then drives the 2nd stage, a PNP transistor in common base configuration, so there
(Read More…)
This is a link to my pictures I posted. watsonspics Pictures, for the most part, of schematics I’ve drawn, using ExpressPCB, free software. There is little or no text. A few may have been drawn by others. Those from Quantsuff (quantsuff.com) have a QS in the name. I’ve received permission from QS to use them.
(Read More…)
