Digital volume control

Digital volume control, Two ladder networks and a buffer each from a volume control with a range of 63 dB. Network R3-R17 provides fine control in steps of 1 dB, whereas network R20-R34 provides coarse control in steps of 8 dB. The desired attenuation is set with aid of multiplexers IC1 and IC3, each of[…]

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Decibel stepper

Decibel stepper, The stepper presented here makes use of nine positions of a 12-position rotary switch. It is, of course, possible to add the three steps. As usual, the amplification factors are arrived at by connecting a number of resistors in series in the feedback circuit. The resistors used here are for the E-96 series,[…]

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Power-on delay

The power supply for this analogue circuit, which affords delays of up to 330 seconds, is taken directly from the mains. The direct voltage at the output of the bridge rectifier is held at 22 V by zenzer diode D5. Resistor R6, which enables C1 to discharge rapidly as soon as the mains is switched off, must[…]

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Overload Indicator

The overload indicator consists of a window comparator that measures the magnitude of an a.f signal. Two of the opamps contained in a TL072 is supplied with a reference voltage by potential divider R1-R2-R3-P1. The outputs of the opamps drive T1 via diodes D1 and D2 (that function as the half-waved rectifier), which in turn actuates D3.[…]

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Digital (tape) Counter

Since there are still tape records about that have no mechanical tape counter, the circuit shown here offers an excellent, electronic add-on for these. It can, of course, also be used to replace a mechanical counter. Furthermore, it can be used for other applications, for instance, as the hoist-height indicator for a model building crane,[…]

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