time stretcher

elektor july/august 1985 Anyone with a fascinating hobby must have felt at one time or another that there is not enough time available for his hobby. Any circuit that can stretch those few hours once or twice a week must, therefore, appeal to many. fclock clock 1% I A = tens of time stretcher From an idea by S Gulikers then runs at half speed only so that it will take two hours before it shows 23.00 h. For the circuit to work correctly, it is essential that the clock signal is divided by two exactly, and this means that resistors R2and R3must be 1 per cent types. This is also the reason that a BS 170 is used as the switching gate; this MOSFET has no saturation voltage. Using a normal transistor with a certain saturation voltage would not cause the clock signal to be divided by two exactly, so that the clock would be fast or slow by minutes within a few days! The circuit as drawn is intended for common-anode displays; if it is to be used with common-cathode displays, simply reverse...