This LED diode test is suggested by the Texas Instruments optoelectronics manual. The transformer current can be between 50 mA and 300 mA and the voltage between 6 and 9 V.
This circuit consists of a monostable multivibrator using the LM3900 transconductance operational...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...