This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with modern equivalents. Output transistors may be BD135 and 136 with heatsinks.
This is the traditional voltage follower configuration with the 741 operational amplifier. The...
This circuit was found in 1960s Radio Electronics. The circuit uses components from that time. The...
This digital indicator circuit was found in the June 1988 issue of Radio Electronics magazine. The circuit...