Practice code oscillator (CB21696E)

In the figure we have an astable multivibrator driving a speaker to produce audio signals for Morse code practice.

Low Power Bluetooth Modules
June 2017 - Mouser Electronics announced the availability of new low-power Bluetooth modules from...
High impedance preamplifier (CB20278E)
In the figure we have the original version of an amplifier with high input impedance, 1.2 M ohms....
Modulated Light ReceiverIR4199S CB13885E (CB13885E)
This sensitive circuit can be designed with FETs such as BF245 and MPF102. The sensor is a silicon...