A basic one transistor regen receiver uses an MPF102 JFET to give the regenerative gain. Also uses two transistors to amplify the audio to drive an earphone. https://www.circuitbasics.com/what-are-fm-receivers/
Archive for the ‘Transistors’ Category:
2024-03-26 HVDC Module Teardown, Operation And Explanation
A 41 min. YouTube video shows operation, tears down, and explains the components. It seems that they are made with cheap chinesium components that are too low voltage ratings so they will fail prematurely if the HVDC is left on a long time or if the spark gap is too wide. Schematic from video is
(Read More…)
2024-03-15 Ferranti Argus “Hearing Aid” Computer
In the “Original Series” chapter this very interesting Wikipedia article talks about the “hearing aid computer” that used the OC-71 germanium transistors which were used in hearing aids and could go only up to 25kHz clock rate. That was quite slow – tube computers could clock at 500kHz. Later models used faster transistors and could
(Read More…)
2024-02-27 MOSFET Driver
The gate driver circuit shown in the screenshot uses BC547s, which are limited to less than 200 mA current. Instead, if the two transistors were BC337 or PN2222A which can easily handle over 500 mA, they could charge and discharge the gate faster, and thus reduce the dissipation in the MOSFET.
2024-02-17 BJT, FET Curve Tracer
This very comprehensive website has a transistor and FET Curve tracer. Also a simpler curve tracer for all components. Click on box to download the schematic, etc. https://www.changpuak.ch/electronics/Curve_Tracer_advanced.php#
2023-07-12 DC-DC Converters That Used Germanium Power Transistors
Me and my high school friend made a DC to DC converter that would give us 30 or so volts at a couple amps from a 12 volt battery. We used germanium power transistors which could not go much above 10 kHz. The Delco’s and the 2N458A’s were our favorites – we managed to push
(Read More…)
2023-06-06 ITT2222 Not Standard Pinout Of PN2222
Caroline Joy Barnhart Your Kit must’ve had those “high quality” Radio Scrap components. 😆 My guess is you got one of the ITT2222 transistors. They made their plastic packaged version of the 2N2222 so that it did *not* conform to the standard E B C of the PN2222 or MPS2222. They were unpopular because they
(Read More…)
2021-11-23 Replace Germanium With Silicon Transistors
I also remember those projects that used the CK722 and 2N107. The last few years I have been repairing older transistor radios with germanium transistors. I have had a few of them with bad germanium output transistors, and I’ve replaced them with silicon PNP transistors, along with a change in base bias resistors. They work
(Read More…)
2020-06-01 Motorola HEP Catalog Transistors pp 10-12
These are scans of the specifications for most of the Motorola HEP line of replacement transistors. Germanium and Silicon. Pages 10, 11, 12.
2019-01-15 Zenith Royal 200 Conversion to Silicon
I’m thinking of pulling up the end of the 100 ohm and looping the lead a few times through the ferrite bead. If that still doesn’t stop the ringing, I’m thinking about replacing the bead with an RF choke. Every time the ringing is reduced the reception gets better. I checked to see if I
(Read More…)
