Heart Beat Monitor

Here is a simple and low-cost cir-cuit of heart beat monitor using readily available components. It uses the piezo electric plate of audible piezobuzzers as the sensing device, which can be purchased for around Rs 2 only from component vendors. The sensor is pressed against human body near the heart region. It should make a solid contact with your palm to convert heart beat sound into low-frequency electrical variations. These electrical variations are amplified by transistor T1 that is configured as a common-emitter amplifier. Amplified signals are coupled to tran sistor T2 for driving the audio power amplifier stage. The speaker reproduces heart beat notes as audible sound.

Circuit diagram :

Heart Beat Monitor Circuit Diagram

Heart Beat Monitor Circuit-Diagram

The two BEL188 silicon transistors used in the power output stage are freely available. In case you use AC188/128 germanium transistors in place of BEL188 silicon transistors, replace 220-ohm resistors with 47-ohm resistors and 680-ohm resistors with 1-kilo-ohm resistors.

Author : Pradeep G. - Copyright : EFY

Comments

OP AMP INTEGRATOR CALCULATOR

Enter the Input Voltage,Vin: Volts Enter the Frequency, f: Hertz Enter the Input Resistance, Rin: Ohms Enter the Value of Capacitor, C: Farads Output Voltage, Vout: Volts OP AMP based Integrator Tutorial and Design

Block diagram of AM transmitter and receiver with explanation

Block diagram of AM transmitter and receiver with explanation AM Transmitter : Transmitters that transmit AM signals are known as AM transmitters. These transmitters are used in medium wave (MW) and short wave (SW) frequency bands for AM broadcast. The MW band has frequencies between 550 KHz and 1650 KHz, and the SW band has frequencies ranging from 3 MHz to 30 MHz. The two types of AM transmitters that are used based on their transmitting powers are: · High Level · Low Level High level transmitters use high level modulation, and low level transmitters use low level modulation. The choice between the two modulation schemes depends on the transmitting power of the AM transmitter. In broadcast transmitters, where the transmitting power may be of the order of kilowatts, high level modulation is employed. In low power transmitters, where only a few watts of transmitting power are required , low...

Using the TLP250 Isolated MOSFET Driver Explanation and Example Circuits

I’ve already shown how to drive an N-channel MOSFET (or even an IGBT) in both high-side and low-side configurations in a multitude of ways. I’ve also explained the principles of driving the MOSFETs in these configurations. The dedicated drivers I’ve shown so far are the TC427 and IR2110. Some people have requested me to write up on MOSFET drive using the very popular TLP250. And I’ll explain that here. The TLP250, like any driver, has an input stage, an output stage and a power supply connection. What’s special about the TLP250 is that the TLP250 is an optically isolated driver, meaning that the input and output are “optically isolated”. The isolation is optical – the input stage is an LED and the receiving output stage is light sensitive (think “photodetector”). Before delving any further, let’s look at the pin configuration and the truth table. Fig. 1 - TLP250 Pin Configuration Fig. 2 - TLP250 Truth Table Fig. 1 clearly shows the input LED side and the receiving photodetector as well...

Do More

Search This Blog