Tender For supply of load cells of various ranges , digital panel meters voltage and current , digital line frequency indicator , d.c. regulated power supply , digital insulation tester , digital l.c.r. bridge , operational amplifier trainer , trainer on basic digital electronics , trainers on power supplier half wave rectifier , scr driven controlled power supply trainer , discrete component trainer with following seven basic modules , trainer on rs485 to rs232 converter , calibration test bench for ac and dc voltmeter , networking toolkit