An Electronic Heartbeat Simulator and a Cardiac Tachometer

The procedure for obtaining an artificial heartbeat with the use of multivibrator techniques is described. The chief feature of this design is the use of well-known circuitry to produce, 1) three pulses of variable amplitude and relatively long periods, and 2) variable time delays between the pulses of up to 0.5 second. Also described is the circuit for a cardiac tachometer with two linear scales, the ranges of which are 0 to 75 and 0 to 180 beats per minute, a response time from zero to full scale (10 seconds), and an accuracy of better than 2 per cent.