DC-DC Converters: T series

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DC-DC converters for vintage calculators: T Series

T Series

ID:	TB-67 (TB67)	Used in:	Canon P2-D (source of info)
Type:	Miniature DC-DC converter transformer
Maker:	TDK
Typical date range:	1980s
Package:	ten pin 12.5mm diameter package
Date coding system:	unknown
Notes:

		In this example point (b) should show a 1V peak to 0.2V trough, decaying square wave, whilst (a) will show a 10V to -2V sharper square wave.

ID:	TC-7A (TC7A)	Used in:	Adler EC8s (source of info)
Type:	Miniature DC-DC converter transformer
Maker:	TDK
Typical date range:	1970s
Package:	nine pin 12.5mm diameter package
Date coding system:	unknown
Notes:

			I just love these vintage Japanese descriptions [Ed]: When the power switch is turned on the base-emitter current of TR1 flows though R4. At the same time TR2 is activated to the ON state, collector current flows through 1 and 2 of the primary coil of the transformer. The current charge magneto flux [original text says magneticflux] increases to the saturation point of the primary coil. When the Magneto flux saturates the primary coil, the direction of the charge of magneto flux suddenly reverses due to the stray capacitance and inductance of the transformer. This variation of magneto flux induces an electromotive force in the secondary circuit. Converter circuit will alternately repeat above action. Note: pin four appears to show a parallel gap with the capacitor. It is actually a 3K3 resistor - their mistake.

			Electrical Specifications
		Pin outs are viewed from the underside	Item	Ratings
			Input voltage	DC +1.8V +3.5V
			Output voltage (1)	DC -10V +/-10V
			Output voltage (2)	DC -28V +/-10V
			Output voltage (3)	AC 3.0V +/-25V
			Conversion efficiency	Over 60%
			Operating temperature	-5°C 50°C
			Storage temperature	-20°C 70°C