Battery operated blood pressure meter - with switch controlling manometer indicators and electromagnets also switching in resistor

摘要

The instrument has a manometer with two indicators, each controlled by an electromagnet. The electronic switch that controls an electromagnet inserts a resistor in the circuit shortly (pref. 100ms) after the magnet is energised, so as to reduce the current to a holding-on level. Pref. the resistor is in series with the electromagnet and is short-circuited by the electronic switch. Each indicator is arranged to remain stationary except when its electromagnet is energised. The equipment switches itself off shortly after the diastolic pressure has been registered.