S.P.T.S. - single pole toggle switch

S.P.T.S. single pole toggle switch As can be seen elsewhere in this issue, a press on/press off function (toggle) from a single pole push button can be achieved quite easily. In this case the circuit is slightly more sophisticated and uses an op-amp to provide the toggle func- tion. Switch bounce, (where the contacts quite literally bounce and provide a number of pulses instead of one) the ever present problem with all mechanical switches, is removed in this circuit. Even though an op-amp is involved, the circuit is still very simple. The gain (ampli- fication) of the op-amp is very high which means that its output can easily be high (+Ub or logic "1") or low (—Ub or logic "0"). A small portion of the output voltage level (for real fanatics about 1/23) is fed back to the non-inverting input of the op-amp. Pressing push button Si will connect capacitor Cl to the inverting input of the op-amp. If the output was low, the op-amp will immediately change state and Cl will begin to cha...