Because these were pnp types, the supply voltage needed to be reversed. It could be thought of as follows (but unfortunately there are no relevant authorities):They adapted the Regency’s circuit to their available transistors. After the initial pioneering work in the semiconductor factory at Ulm, it is clear that the Hanover factory became active only after the release of Regency receiver. Other experimental circuits of the time, as well as the upcoming transistor receivers from 1955 below, deviate from its circuit design significantly.A great similarity is apparent when comparing the circuit of the "Telefunken TR-1" with the "Regency TR-1" (Fig. The circuit of the self-oscillating mixer stage, the base bias voltage of the second IF stage from the AF power stage, the unusual IF of 262KHz and the supply voltage of 22.5 V are all characteristic of the device. It was a true international sensation (2).The circuitry of the Regency shows some peculiarities.
It was the first mass-produced transistor receiver in the world and arrived earlier than the professional world expected. In the USA on the 18th October 1954, the "Regency TR-1," developed by Texas Instruments was launched on the market. Here we add the following commentary to the article "Telefunken Pocket Radios from 1955-1960" in Funkgeschichte Nr.
Translated from: Gebert W Anmerkungen zu den Schaltungen der ersten Transistorradios Funkgeschichte 115 (1997) 241-44 by W Gebert and M Burgess Comments on the Circuits of the first Transistor Radios
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